Operators and Operands
Operators and Operands
Fundamental C# Operators
Introduction
An operation is an action performed on one or more values either to modify the value held by one or both of the variables, or to produce a new value by combining existing values. Therefore, an operation is performed using at least one symbol and at least one value. The symbol used in an operation is called an operator. A value involved in an operation is called an operand.
A unary operator is an operator that performs its operation on only one operand. An operator is referred to as binary if it operates on two operands.
Practical Learning: Introducing Operators and Operands
Curly brackets are probably the most used and the most tolerant operators of C#. Fundamentally, curly brackets are used to create a section of code. As such they are required to delimit the bodies of namespaces, classes, structures, exceptions, etc. They are also optionally used in conditional statements. Curly brackets are also used to create variable scope.
Practical Learning: Using Curly Brackets
class Order
{
}Parentheses are used to isolate a group of items that must be considered as belonging to one entity. For example, parentheses are used to differentiate a method such as Main from a regular variable. Here is an example:
class Exercise
{
static void Main()
{
}
}
Parentheses can also be used to isolate an operation or an expression with regard to another operation or expression.
Practical Learning: Using Parentheses
class Order
{
static void Main()
{
}
}
Semi-Colon;
The semi-colon is used to indicate the end of an expression or a declaration. Here is an example:
int number;
As we will learn, there are other uses of the semi-colon.
Practical Learning: Introducing the Semi-Colon
class Order
{
static void Main()
{
double mondayDiscount;
}
}The comma is used to separate variables used in a group. For example, a comma can be used to delimit the names of variables that are declared with the same data type. Here is an example:
class Exercise
{
static void Main()
{
string firstName, lastName, fullName;
}
}
The comma can also be used to separate the member of an enumeration or the arguments of a method. We will review all of them when the time comes.
Practical Learning: Using Commas
class Order
{
static void Main()
{
string customerName, homePhone;
int numberOfShirts, numberOfPants, numberOfDresses;
double priceOneShirt, priceAPairOfPants, priceOneDress;
int orderMonth, orderDay, orderYear;
double mondayDiscount;
}
}
When you declare a variable, a memory space is reserved for it. That memory space may be empty until you fill it with a value. To "put" a value in the memory space allocated to a variable, you can use the assignment operator represented as =. Based on this, the assignment operation gives a value to a variable. Its syntax is:
VariableName = Value
The VariableName factor must be a valid variable name. It cannot be a value such as a numeric value or a (double-quoted) string. Here is an example that assigns a numeric value to a variable:
class Exercise
{
static void Main()
{
double salary;
// Using the assignment operator
salary = 12.55;
}
}
Once a variable has been declared and assigned a value, you can call Write() or WriteLine() to display its value. Here is an example:
class Exercise
{
static void Main()
{
double salary;
// Using the assignment operator
salary = 12.55;
System.Console.Write("Employee's Hourly Salary: ");
System.Console.WriteLine(salary);
}
}
This would produce:
Employee's Hourly Salary: $12.55
The above code declares a variable before assigning it a value. You will usually perform this assignment when you want to change the value held by a variable. Providing a starting value to a variable when the variable is declared is referred to as initializing the variable. Here is an example:
class Exercise
{
static void Main()
{
// Using the assignment operator
double salary = 12.55;
System.Console.Write("Employee's Hourly Salary: ");
System.Console.WriteLine(salary);
}
}
We saw that you can declare various variables at once by using the same data type but separating their names with commas. When doing this, you can also initialize each variable by assigning it the desired value before the comma or the semi-colon. Here is an example:
class Exercise
{
static void Main()
{
// Initializing various variables when declaring them with the same data type
double value1 = 224.58, value2 = 1548.26;
System.Console.Write("Value 1 = ");
System.Console.WriteLine(value1);
System.Console.Write("Value 2 = ");
System.Console.WriteLine(value2);
System.Console.WriteLine();
}
}
This would produce:
Value 1 = 224.58 Value 2 = 1548.26
Practical Learning: Assigning Values to Variables
class Order
{
static void Main()
{
string customerName, homePhone;
int numberOfShirts = 5,
numberOfPants = 2,
numberOfDresses = 0;
double priceOneShirt = 0.95,
priceAPairOfPants = 2.95,
priceOneDress = 4.55;
int orderMonth = 3, orderDay = 15, orderYear = 2002;
double mondayDiscount = 0.25; // 25%;
}
}The double-quote " is used to delimit a string. Like the single-quote, the double-quote is usually combined with another. Between the combination of double-quotes, you can include an empty space, a character, a word, or a group of words, making it a string. Here is an example:
class Exercise
{
static void Main()
{
System.Console.WriteLine("The Wonderful World of C#!!!");
}
}
A double-quoted string can also be declared and then assigned to a variable.
Practical Learning: Using Quotes
class Order
{
static void Main()
{
string customerName = "James Burreck",
homePhone = "(202) 301-7030";
int numberOfShirts = 1,
numberOfPants = 1,
numberOfDresses = 1;
double priceOneShirt = 0.95,
priceAPairOfPants = 2.95,
priceOneDress = 4.55;
int orderMonth = 3, orderDay = 15, orderYear = 2002;
double mondayDiscount = 0.25; // 25%;
System.Console.WriteLine("-/- Georgetown Cleaning Services -/-");
System.Console.WriteLine("========================");
System.Console.Write("Customer: ");
System.Console.WriteLine(customerName);
System.Console.Write("Home Phone: ");
System.Console.WriteLine(homePhone);
System.Console.Write("Order Date: ");
System.Console.Write(orderMonth);
System.Console.Write('/');
System.Console.Write(orderDay);
System.Console.Write('/');
System.Console.WriteLine(orderYear);
System.Console.WriteLine("------------------------");
System.Console.WriteLine("Item Type Qty Sub-Total");
System.Console.WriteLine("------------------------");
System.Console.Write("Shirts ");
System.Console.Write(numberOfShirts);
System.Console.Write(" ");
System.Console.WriteLine(priceOneShirt);
System.Console.Write("Pants ");
System.Console.Write(numberOfPants);
System.Console.Write(" ");
System.Console.WriteLine(priceAPairOfPants);
System.Console.Write("Dresses ");
System.Console.Write(numberOfDresses);
System.Console.Write(" ");
System.Console.WriteLine(priceOneDress);
System.Console.WriteLine("------------------------");
System.Console.Write("Monday Discount: ");
System.Console.Write(mondayDiscount);
System.Console.WriteLine('%');
System.Console.WriteLine("========================");
}
}-/- Georgetown Cleaning Services -/- ======================== Customer: James Burreck Home Phone: (202) 301-7030 Order Date: 3/15/2002 ------------------------ Item Type Qty Sub-Total ------------------------ Shirts 1 0.95 Pants 1 2.95 Dresses 1 4.55 ------------------------ Monday Discount: 0.25% ========================
Square Brackets [ ]
Square brackets are mostly used to control the dimension or index of an array. We will learn how to use them when we study arrays.
Algebra uses a type of ruler to classify numbers. This ruler has a middle position of zero. The numbers on the left side of the 0 are referred to as negative while the numbers on the right side of the rulers are considered positive:
| -∞ | -6 | -5 | -4 | -3 | -2 | -1 | 1 | 2 | 3 | 4 | 5 | 6 | +∞ | |||
| 0 | ||||||||||||||||
| -∞ | -6 | -5 | -4 | -3 | -2 | -1 | 1 | 2 | 3 | 4 | 5 | 6 | +∞ | |||
A value on the right side of 0 is considered positive. To express that a number is positive, you can write a + sign on its left. Examples are +4, +228, +90335. In this case the + symbol is called a unary operator because it acts on only one operand. The positive unary operator, when used, must be positioned on the left side of its operand, never on the right side.
As a mathematical convention, when a value is positive, you don't need to express it with the + operator. Just writing the number without any symbol signifies that the number is positive. Therefore, the numbers +4, +228, and +90335 can be, and are better, expressed as 4, 228, 90335. Because the value doesn't display a sign, it is referred as unsigned.
To express a variable as positive or unsigned, you can just type it. here is an example:
class Exercise
{
static void Main()
{
// Displaying an unsigned number
System.Console.Write("Number = ");
System.Console.WriteLine(+802);
}
}
This would produce:
Number = 802
As you can see on the above ruler, in order to express any number on the left side of 0, it must be appended with a sign, namely the - symbol. xamples are -12, -448, -32706. A value accompanied by - is referred to as negative. The - sign must be typed on the left side of the number it is used to negate. Remember that if a number does not have a sign, it is considered positive. Therefore, whenever a number is negative, it MUST have a - sign. In the same way, if you want to change a value from positive to negative, you can just add a - sign to its left.
Here is an example that uses two variables. One has a positive value while the other has a negative value:
class Exercise
{
static void Main()
{
// Displaying an unsigned number
System.Console.Write("First Number ");
System.Console.WriteLine(+802);
// Displaying a negative number
System.Console.Write("Second Number ");
System.Console.WriteLine(-802);
}
}
This would produce:
First Number 802 Second Number -802
Introduction to the Addition Operations
Overview
The addition is an operation used to add things of the same nature one to another, as many as necessary. Sometimes, the items are added one group to another. The concept is still the same, except that this last example is faster. The addition is performed in mathematics using the + sign. The same sign is used in C#. Here is an example that adds two numbers:
class Exercise
{
static void Main()
{
System.Console.Write("244 + 835 = ");
System.Console.WriteLine(244 + 835);
}
}
Here is the result:
244 + 835 = 1079
You can also add some values already declared and initialized in your program. You can also get the values from the user.
Practical Learning: Using the Addition Operator
class Order
{
static void Main()
{
string customerName = "James Burreck",
homePhone = "(202) 301-7030";
int numberOfShirts = 1,
numberOfPants = 1,
numberOfDresses = 1;
int totalNumberOfItems;
double priceOneShirt = 0.95,
priceAPairOfPants = 2.95,
priceOneDress = 4.55;
int orderMonth = 3, orderDay = 15, orderYear = 2019;
totalNumberOfItems = numberOfShirts + numberOfPants + numberOfDresses;
System.Console.WriteLine("-/- Georgetown Cleaning Services -/-");
System.Console.WriteLine("========================");
System.Console.Write("Customer: ");
System.Console.WriteLine(customerName);
System.Console.Write("Home Phone: ");
System.Console.WriteLine(homePhone);
System.Console.Write("Order Date: ");
System.Console.Write(orderMonth);
System.Console.Write('/');
System.Console.Write(orderDay);
System.Console.Write('/');
System.Console.WriteLine(orderYear);
System.Console.WriteLine("------------------------");
System.Console.WriteLine("Item Type Qty Sub-Total");
System.Console.WriteLine("------------------------");
System.Console.Write("Shirts ");
System.Console.Write(numberOfShirts);
System.Console.Write(" ");
System.Console.WriteLine(priceOneShirt);
System.Console.Write("Pants ");
System.Console.Write(numberOfPants);
System.Console.Write(" ");
System.Console.WriteLine(priceAPairOfPants);
System.Console.Write("Dresses ");
System.Console.Write(numberOfDresses);
System.Console.Write(" ");
System.Console.WriteLine(priceOneDress);
System.Console.WriteLine("------------------------");
System.Console.Write("Number of Items: ");
System.Console.WriteLine(totalNumberOfItems);
System.Console.WriteLine("========================");
}
}-/- Georgetown Cleaning Services -/- ======================== Customer: James Burreck Home Phone: (202) 301-7030 Order Date: 3/15/2019 ------------------------ Item Type Qty Sub-Total ------------------------ Shirts 1 0.95 Pants 1 2.95 Dresses 1 4.55 ------------------------ Number of Items: 3 ========================
Incrementing a Variable
We are used to counting numbers such as 1, 2, 3, 4, etc. In reality, when counting such numbers, we are simply adding 1 to a number in order to get the next number in the range. The simplest technique of incrementing a value consists of adding 1 to it. After adding 1, the value or the variable is (permanently) modified and the variable would hold the new value. This is illustrated in the following example:
// This program studies value incrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of incrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value = value + 1;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Techniques of incrementing a value Value = 12 Value = 13
C# provides a special operator that takes care of this operation. The operator is called the increment operator and is represented by ++. Instead of writing Value = Value + 1, you can write Value++ and you would get the same result. The above program can be re-written as follows:
// This program studies value incrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of incrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value++;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
The ++ is a unary operator because it operates on only one variable. It is used to modify the value of the variable by adding 1 to it. Every time the Value++ is executed, the compiler takes the previous value of the variable, adds 1 to it, and the variable holds the incremented value:
// This program studies value incrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of incrementing a value");
value++;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value++;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
Value++;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Techniques of incrementing a value Value = 13 Value = 14 Value = 15
Pre and Post-Increment
When using the ++ operator, the position of the operator with regard to the variable it is modifying can be significant. To increment the value of the variable before re-using it, you should position the operator on the left of the variable:
// This program studies value incrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of incrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
System.Console.Write("Value = ");
System.Console.WriteLine(++value);
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Techniques of incrementing a value Value = 12 Value = 13 Value = 13
When writing ++Value, the value of the variable is incremented before being called. On the other hand, if you want to first use a variable, then increment it, in other words, if you want to increment the variable after calling it, position the increment operator on the right side of the variable:
// This program studies value incrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of incrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
System.Console.Write("Value = ");
System.Console.WriteLine(value++);
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Techniques of incrementing a value Value = 12 Value = 12 Value = 13
Compound Addition
It is not unusual to add a constant value to a variable. All you have to do is to declare another variable that would hold the new value. Here is an example:
// This program studies value incrementing and decrementing
public class Exercise
{
static void Main()
{
double value = 12.75;
double newValue;
System.Console.WriteLine("Techniques of incrementing and decrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
newValue = value + 2.42;
System.Console.Write("Value = ");
System.Console.WriteLine(newValue);
}
}
This would produce:
Techniques of incrementing and decrementing a value Value = 12.75 Value = 15.17
The above technique requires that you use an extra variable in your application. The advantage is that each value can hold its own value although the value of the second variable depends on whatever would happen to the original or source variable. Sometimes in your program you will not need to keep the original value of the source variable. You may want to permanently modify the value that a variable is holding. In this case, you can perform the addition operation directly on the variable by adding the desired value to the variable. This operation modifies whatever value a variable is holding and does not need an additional variable.
To add a value to a variable and change the value that the variable is holding, you can combine the assignment "=" and the addition "+" operators to produce a new operator as +=. Here is an example:
// This program studies value incrementing and decrementing
public class Exercise
{
static void Main()
{
var value = 12.75;
System.Console.WriteLine("Techniques of incrementing and decrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value += 2.42;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This program produces the same result as the previous.
Adding Strings
Introduction
You can apply the addition operation on strings the same way you would on numeric calues. You can use the + operator on strings as in "Pie" + "Chart". This would produce "PieChart". You can also apply the operator to string variables. Here is an example:
class Exercise
{
static void Main()
{
var firstName = "Alexander";
var lastName = "Kallack";
var fullName = firstName + " " + lastName;
System.Console.Write("Full Name: ");
System.Console.WriteLine(fullName);
}
}
This would produce:
Full Name: Alexander Kallack Press any key to continue . . .
String Addition and Other Types
You can add the value of any type to a string. The result is a new string. Here is an example:
class EmployeesRecords
{
static void Main()
{
double rate = 17.82;
string salary = "Hourly Salary: ";
string result = salary + rate;
System.Console.WriteLine(result);
}
Writing an Addition
We already know that, to display a constant value, you can put it in the parentheses of System.Console.Write() or System.Console.WriteLine(). Instead of a constant value, you include an addition in those parentheses. Here is an example that adds two strings in the parentheses of System.Console.WriteLine():
class EmployeesRecords
{
static void Main()
{
System.Console.WriteLine("Red Oak " + "High School");
}
}
Of course, you can also add more than two strings. You can also add variables. You can also add variables and regular strings. Here is an example:
class EmployeesRecords
{
static void Main()
{
string mainTitle = "Red Oak High School";
string subTitle = "Students Records";
System.Console.Write(mainTitle + " - " + subTitle);
}
}
In the same way, in the parentheses, you can add any value to a string. Here is an example:
class EmployeesRecords
{
static void Main()
{
string salary = "Hourly Salary: ";
double rate = 17.82;
System.Console.WriteLine(salary + rate);
}
}
Compound Addition on Strings
As seein in the previous section, to add two strings, you can separate them with the + operator. This would produce a new value. You use such a variable if you plan to use the result more than once. If you want to use the result only only once, you can separate the strings or variables with the += operator. After the operation, the left string would now hold its own value followed by the other string. Here is an example:
class Exercise
{
static void Main()
{
var firstName = "Alexander";
var lastName = "Kallack";
var fullName = firstName;
fullName += lastName;
System.Console.Write("Full Name: ");
System.Console.WriteLine(fullName);
}
}
In the same way, you can perform a compound addition on a string and a value of any type. Here is an example:
class EmployeesRecords
{
static void Main()
{
string result = "";
double rate = 17.82;
string salary = "Hourly Salary: ";
result += salary;
System.Console.WriteLine(result);
result += rate;
System.Console.WriteLine(result);
}
}
This would produce:
Hourly Salary: Hourly Salary: 17.82 -------------------- Press any key to continue . . .
The Multiplication Operations
Introduction
The multiplication allows adding one value to itself a certain number of times, set by a second value. As an example, instead of adding a value to itself in this manner: A + A + A + A, since the variable a is repeated over and over again, you could simply find out how many times A is added to itself, then multiply a by that number which, is this case, is 4. This would mean adding a to itself 4 times, and you would get the same result.
Just like the addition, the multiplication is associative: a * b * c = c * b * a. When it comes to programming syntax, the rules we learned with the addition operation also apply to the multiplication.
Here is an example:
class Exercise
{
static void Main()
{
// Initializing various variables when declaring them with the same data type
double value1 = 224.58, value2 = 1548.26;
var result = value1 * value2;
System.Console.Write(value1);
System.Console.Write(" * ");
System.Console.Write(value2);
System.Console.Write(" = ");
System.Console.WriteLine(result);
System.Console.WriteLine();
}
}
This would produce:
224.58 * 1548.26 = 347708.2308 Press any key to continue . . .
Practical Learning: Using the Multiplication Operator
class Order
{
static void Main()
{
const double priceOneShirt = 0.95;
const double priceAPairOfPants = 2.95;
const double priceOneDress = 4.55;
string customerName = "James Burreck",
homePhone = "(202) 301-7030";
int numberOfShirts = 5,
numberOfPants = 2,
numberOfDresses = 3;
int totalNumberOfItems;
double subTotalShirts, subTotalPants, subTotalDresses;
double totalOrder;
int orderMonth = 3, orderDay = 15, orderYear = 2002;
totalNumberOfItems = numberOfShirts + numberOfPants + numberOfDresses;
subTotalShirts = priceOneShirt * numberOfShirts;
subTotalPants = priceAPairOfPants * numberOfPants;
subTotalDresses = numberOfDresses * priceOneDress;
totalOrder = subTotalShirts + subTotalPants + subTotalDresses;
System.Console.WriteLine("-/- Georgetown Cleaning Services -/-");
System.Console.WriteLine("====================================");
System.Console.Write("Customer: ");
System.Console.WriteLine(customerName);
System.Console.Write("Home Phone: ");
System.Console.WriteLine(homePhone);
System.Console.Write("Order Date: ");
System.Console.Write(orderMonth);
System.Console.Write('/');
System.Console.Write(orderDay);
System.Console.Write('/');
System.Console.WriteLine(orderYear);
System.Console.WriteLine("------------------------------------");
System.Console.WriteLine("Item Type Qty Unit/Price Sub-Total");
System.Console.WriteLine("------------------------------------");
System.Console.Write("Shirts ");
System.Console.Write(numberOfShirts);
System.Console.Write(" ");
System.Console.Write(priceOneShirt);
System.Console.Write(" ");
System.Console.WriteLine(subTotalShirts);
System.Console.Write("Pants ");
System.Console.Write(numberOfPants);
System.Console.Write(" ");
System.Console.Write(priceAPairOfPants);
System.Console.Write(" ");
System.Console.WriteLine(subTotalPants);
System.Console.Write("Dresses ");
System.Console.Write(numberOfDresses);
System.Console.Write(" ");
System.Console.Write(priceOneDress);
System.Console.Write(" ");
System.Console.WriteLine(subTotalDresses);
System.Console.WriteLine("------------------------------------");
System.Console.Write("Number of Items: ");
System.Console.WriteLine(totalNumberOfItems);
System.Console.Write("Total Order: ");
System.Console.WriteLine(totalOrder);
System.Console.WriteLine("====================================");
}
}-/- Georgetown Cleaning Services -/- ==================================== Customer: James Burreck Home Phone: (202) 301-7030 Order Date: 3/15/2002 ------------------------------------ Item Type Qty Unit/Price Sub-Total ------------------------------------ Shirts 5 0.95 4.75 Pants 2 2.95 5.90 Dresses 3 4.55 13.65 ------------------------------------ Number of Items: 10 Total Order: 24.30 ====================================
Compound Multiplication
We saw that you could add or subtract a value to a variable and assign the result to the same variable. You can perform the same operation with the multiplication. Here is an example:
class Exercise
{
static void Main()
{
double value = 12.75;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value = Value * 2.42;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Value = 12.75 Value = 30.855 Press any key to continue . . .
To make this operation easy, the C# language supports the compound multiplication assignment operator represented as *=. To use it, use the *= operator and assign the desired value to the variable. Here is an example:
class Exercise
{
static void Main()
{
double value = 12.75;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value *= 2.42;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
Introduction
The subtraction operation is used to take out or subtract a value from another value. It is essentially the opposite of the addition. The subtraction is performed with the - sign. Here is an example:
class Exercise
{
static void Main()
{
// Values used in this program
double value1 = 224.58, value2 = 1548.26;
var result = value1 - value2;
System.Console.Write(value1);
System.Console.Write(" - ");
System.Console.Write(value2);
System.Console.Write(" = ");
System.Console.WriteLine(result);
}
}
This would produce:
224.58 - 1548.26 = -1323.68 Press any key to continue . . .
Unlike the addition, the subtraction is not associative. In other words, a - b - c is not the same as c - b - a. Consider the following program that illustrates this:
class Exercise
{
static void Main()
{
// This tests whether the addition is associative
System.Console.WriteLine(" =+= Addition =+=");
System.Console.Write("128 + 42 + 5 = ");
System.Console.WriteLine(128 + 42 + 5);
System.Console.Write(" 5 + 42 + 128 = ");
System.Console.WriteLine(5 + 42 + 128);
System.Console.WriteLine();
// This tests whether the subtraction is associative
System.Console.WriteLine(" =-= Subtraction =-=");
System.Console.Write("128 - 42 - 5 = ");
System.Console.WriteLine(128 - 42 - 5);
System.Console.Write(" 5 - 42 - 128 = ");
System.Console.WriteLine(5 - 42 - 128);
System.Console.WriteLine();
}
}
This would produce:
=+= Addition =+= 128 + 42 + 5 = 175 5 + 42 + 128 = 175 =-= Subtraction =-= 128 - 42 - 5 = 81 5 - 42 - 128 = -165
Notice that both operations of the addition convey the same result. In the subtraction section, the numbers follow the same order but produce different results.
Practical Learning: Using the Subtraction Operator
class Order
{
static void Main()
{
const double priceOneShirt = 0.95;
const double priceAPairOfPants = 2.95;
const double priceOneDress = 4.55;
const double salestaxRate = 0.0575; // 5.75%
string customerName = "James Burreck",
homePhone = "(202) 301-7030";
int numberOfShirts = 5,
numberOfPants = 2,
numberOfDresses = 3;
int totalNumberOfItems;
double subTotalShirts, subTotalPants, subTotalDresses;
double taxAmount, totalOrder, netPrice;
int orderMonth = 3, orderDay = 15, orderYear = 2002;
totalNumberOfItems = numberOfShirts + numberOfPants + numberOfDresses;
subTotalShirts = priceOneShirt * numberOfShirts;
subTotalPants = priceAPairOfPants * numberOfPants;
subTotalDresses = numberOfDresses * priceOneDress;
totalOrder = subTotalShirts + subTotalPants + subTotalDresses;
taxAmount = totalOrder * salestaxRate;
netPrice = totalOrder - taxAmount;
System.Console.WriteLine("-/- Georgetown Cleaning Services -/-");
System.Console.WriteLine("====================================");
System.Console.Write("Customer: ");
System.Console.WriteLine(customerName);
System.Console.Write("Home Phone: ");
System.Console.WriteLine(homePhone);
System.Console.Write("Order Date: ");
System.Console.Write(orderMonth);
System.Console.Write('/');
System.Console.Write(orderDay);
System.Console.Write('/');
System.Console.WriteLine(orderYear);
System.Console.WriteLine("------------------------------------");
System.Console.WriteLine("Item Type Qty Unit/Price Sub-Total");
System.Console.WriteLine("------------------------------------");
System.Console.Write("Shirts ");
System.Console.Write(numberOfShirts);
System.Console.Write(" ");
System.Console.Write(priceOneShirt);
System.Console.Write(" ");
System.Console.WriteLine(subTotalShirts);
System.Console.Write("Pants ");
System.Console.Write(numberOfPants);
System.Console.Write(" ");
System.Console.Write(priceAPairOfPants);
System.Console.Write(" ");
System.Console.WriteLine(subTotalPants);
System.Console.Write("Dresses ");
System.Console.Write(numberOfDresses);
System.Console.Write(" ");
System.Console.Write(priceOneDress);
System.Console.Write(" ");
System.Console.WriteLine(subTotalDresses);
System.Console.WriteLine("------------------------------------");
System.Console.Write("Number of Items: ");
System.Console.WriteLine(totalNumberOfItems);
System.Console.Write("Total Order: ");
System.Console.WriteLine(totalOrder);
System.Console.Write("Tax Rate: ");
System.Console.Write(salestaxRate * 100);
System.Console.WriteLine('%');
System.Console.Write("Tax Amount: ");
System.Console.WriteLine(taxAmount);
System.Console.Write("Net Price: ");
System.Console.WriteLine(netPrice);
System.Console.WriteLine("====================================");
}
}-/- Georgetown Cleaning Services -/- ==================================== Customer: James Burreck Home Phone: (202) 301-7030 Order Date: 3/15/2002 ------------------------------------ Item Type Qty Unit/Price Sub-Total ------------------------------------ Shirts 5 0.95 4.75 Pants 2 2.95 5.90 Dresses 3 4.55 13.65 ------------------------------------ Number of Items: 10 Total Order: 24.30 Tax Rate: 5.7500% Tax Amount: 1.397250 Net Price: 22.902750 ====================================
Decrementing a Variable
When counting numbers backward, such as 8, 7, 6, 5, etc, we are in fact subtracting 1 from a value in order to get the lesser value. This operation is referred to as decrementing a value. This operation works as if a value is decremented by 1, as in Value = Value – 1:
// This program studies value decrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of decrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value = value - 1;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Techniques of decrementing a value Value = 12 Value = 11
As done to increment, C# provides a quicker way of subtracting 1 from a value. This is done using the decrement operator, that is --. To use the decrement operator, type –- on the left or the right side of the variable when this operation is desired. Using the decrement operator, the above program could be written:
// This program studies value decrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of decrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value--;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
Pre-Decrementing a Value
Once again, the position of the operator can be important. If you want to decrement the variable before calling it, position the decrement operator on the left side of the operand. This is illustrated in the following program:
// This program studies value decrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of decrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
System.Console.Write("Value = ");
System.Console.WriteLine(--value);
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Techniques of decrementing a value Value = 12 Value = 11 Value = 11
If you plan to decrement a variable only after it has been accessed, position the operator on the right side of the variable. Here is an example:
// This program studies value decrementing
public class Exercise
{
static void Main()
{
var value = 12;
System.Console.WriteLine("Techniques of decrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
System.Console.Write("Value = ");
System.Console.WriteLine(Value--);
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Techniques of decrementing a value Value = 12 Value = 12 Value = 11
Compound Subtraction
You may want to subtract a constant value from a variable. To decrement a value from a variable, use the subtraction and apply the same technique. This is done with the -= operator. Here is an example:
// This program studies value incrementing and decrementing
public class Exercise
{
static void Main()
{
var value = 12.75;
System.Console.WriteLine("Techniques of incrementing and decrementing a value");
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value -= 2.42;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Techniques of incrementing and decrementing a value Value = 12.75 Value = 10.33
Introduction
Dividing an item means cutting it in pieces or fractions of a set value. For example, when you cut an apple in the middle, you are dividing it in 2 pieces. If you cut each one of the resulting pieces, you will get 4 pieces or fractions. This is considered that you have divided the apple in 4 parts. Therefore, the division is used to get the fraction of one number in terms of another. The division is performed with the forward slash /. Here is an example:
class Exercise
{
static void Main()
{
// Initializing various variables when declaring them with the same data type
double value1 = 224.58, value2 = 1548.26;
var result = value1 / value2;
System.Console.Write(value1);
System.Console.Write(" / ");
System.Console.Write(value2);
System.Console.Write(" = ");
System.Console.WriteLine(result);
System.Console.WriteLine();
}
}
This would produce:
224.58 / 1548.26 = 0.145053156446592 Press any key to continue . . .
When performing the division, be aware of its many rules. Never divide by zero (0). Make sure that you know the relationship(s) between the numbers involved in the operation.
Practical Learning: Using the Division Operator
class Order
{
static void Main()
{
const double priceOneShirt = 0.95;
const double priceAPairOfPants = 2.95;
const double priceOneDress = 4.55;
const double discountRate = 0.20; // 20%
const double taxRate = 5.75; // 5.75%
string customerName = "James Burreck",
homePhone = "(202) 301-7030";
int numberOfShirts = 5,
numberOfPants = 2,
numberOfDresses = 3;
int totalNumberOfItems;
double subTotalShirts, subTotalPants, subTotalDresses;
double DiscountAmount, totalOrder, netPrice, taxAmount, salesTotal;
double amountTended, difference;
int orderMonth = 3, orderDay = 15, orderYear = 2002;
totalNumberOfItems = numberOfShirts + numberOfPants + numberOfDresses;
subTotalShirts = priceOneShirt * numberOfShirts;
subTotalPants = priceAPairOfPants * numberOfPants;
subTotalDresses = numberOfDresses * priceOneDress;
totalOrder = subTotalShirts + subTotalPants + subTotalDresses;
DiscountAmount = totalOrder * discountRate;
netPrice = totalOrder - DiscountAmount;
taxAmount = totalOrder * taxRate / 100;
salesTotal = netPrice + taxAmount;
amountTended = 50;
difference = amountTended - salesTotal;
System.Console.WriteLine("-/- Georgetown Cleaning Services -/-");
System.Console.WriteLine("====================================");
System.Console.Write("Customer: ");
System.Console.WriteLine(customerName);
System.Console.Write("Home Phone: ");
System.Console.WriteLine(homePhone);
System.Console.Write("Order Date: ");
System.Console.Write(orderMonth);
System.Console.Write('/');
System.Console.Write(orderDay);
System.Console.Write('/');
System.Console.WriteLine(orderYear);
System.Console.WriteLine("------------------------------------");
System.Console.WriteLine("Item Type Qty Unit/Price Sub-Total");
System.Console.WriteLine("------------------------------------");
System.Console.Write("Shirts ");
System.Console.Write(numberOfShirts);
System.Console.Write(" ");
System.Console.Write(priceOneShirt);
System.Console.Write(" ");
System.Console.WriteLine(subTotalShirts);
System.Console.Write("Pants ");
System.Console.Write(numberOfPants);
System.Console.Write(" ");
System.Console.Write(priceAPairOfPants);
System.Console.Write(" ");
System.Console.WriteLine(subTotalPants);
System.Console.Write("Dresses ");
System.Console.Write(numberOfDresses);
System.Console.Write(" ");
System.Console.Write(priceOneDress);
System.Console.Write(" ");
System.Console.WriteLine(subTotalDresses);
System.Console.WriteLine("------------------------------------");
System.Console.Write("Number of Items: ");
System.Console.WriteLine(totalNumberOfItems);
System.Console.Write("Total Order: ");
System.Console.WriteLine(totalOrder);
System.Console.Write("Discount Rate: ");
System.Console.Write(discountRate * 100);
System.Console.WriteLine('%');
System.Console.Write("Discount Amount: ");
System.Console.WriteLine(DiscountAmount);
System.Console.Write("After Discount: ");
System.Console.WriteLine(netPrice);
System.Console.Write("Tax Rate: ");
System.Console.Write(taxRate);
System.Console.WriteLine('%');
System.Console.Write("Tax Amount: ");
System.Console.WriteLine(taxAmount);
System.Console.Write("Net Price: ");
System.Console.WriteLine(salesTotal);
System.Console.WriteLine("====================================");
System.Console.Write("Amount Tended: ");
System.Console.WriteLine(amountTended);
System.Console.Write("Difference: ");
System.Console.WriteLine(difference);
System.Console.WriteLine("====================================");
}
}-/- Georgetown Cleaning Services -/- ==================================== Customer: James Burreck Home Phone: (202) 301-7030 Order Date: 3/15/2002 ------------------------------------ Item Type Qty Unit/Price Sub-Total ------------------------------------ Shirts 5 0.95 4.75 Pants 2 2.95 5.90 Dresses 3 4.55 13.65 ------------------------------------ Number of Items: 10 Total Order: 24.30 Discount Rate: 20.00% Discount Amount: 4.8600 After Discount: 19.4400 Tax Rate: 5.75% Tax Amount: 1.39725 Net Price: 20.83725 ==================================== Amount Tended: 50 Difference: 29.16275 ====================================
Compound Division
Remember that you can add, subtract, or multiply a value to a variable and assign the result to the variable itself. You can also perform this operation using the division. Here is an example:
class Exercise
{
static void Main()
{
double value = 12.75;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value = value / 2.42;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
This would produce:
Value = 12.75 Value = 5.26859504132231 Press any key to continue . . .
To perform this operation faster, the C# language provides the /= operator. Here is an example of using it:
class Exercise
{
static void Main()
{
double value = 12.75;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
value /= 2.42;
System.Console.Write("Value = ");
System.Console.WriteLine(value);
}
}
Introduction
The division program gives a result of a number with decimal values if you provide an odd number (like 147), which is fine in some circumstances. Sometimes you will want to get the value remaining after a division renders a natural result. Imagine you have 26 kids at a football (soccer) stadium and they are about to start. You know that you need 11 kids for each team to start. If the game starts with the right amount of players, how many will seat and wait?
The remainder operation is performed with the percent sign (%) which is gotten from pressing Shift + 5.
Here is an example:
class Exercise
{
static void Main()
{
var players = 18;
var remainder = players % 11;
// When the game starts, how many players will wait?.
System.Console.Write("Out of ");
System.Console.Write(players);
System.Console.Write(" players, ");
System.Console.Write(remainder);
System.Console.WriteLine(" players will have to wait when the game starts.\n");
}
}
This would produce:
Out of 18 players, 7 players will have to wait when the game starts. Press any key to continue . . .
The Compound Remainder
As seen with the other arithmetic operators, you can find the remainder of a variable and assign the result to the variable itself. Here is an example:
class Exercise
{
static void Main()
{
var players = 18;
// When the game starts, how many players will wait?.
System.Console.Write("Out of ");
System.Console.Write(players);
System.Console.Write(" players, ");
players = players % 11;
System.Console.Write(players);
System.Console.WriteLine(" players will have to wait when the game starts.\n");
}
}
To support a faster version of this operation, the C# language provides the compound remainder operator represented as %=. To use it, assign its value to the variable. Here is an example:
class Exercise
{
static void Main()
{
var Players = 18;
// When the game starts, how many players will wait?.
System.Console.Write("Out of ");
System.Console.Write(players);
System.Console.Write(" players, ");
players %= 11;
System.Console.Write(players);
System.Console.WriteLine(" players will have to wait when the game starts.\n");
}
}
Practical Learning: Ending the Lesson
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