Arithmetic: The Mantissa and Exponent |
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double ldexp(double x, int y); long double ldexpl(long double x, int y); The C/C++ ldexp() function takes the mantissa and the exponent numbers and returns a floating number. The function uses the formula: Result = x * 2y Here is an example: //--------------------------------------------------------------------------- void __fastcall TForm1::Button1Click(TObject *Sender) { double x, Result; int y; x = StrToFloat(Edit1->Text); y = StrToInt(Edit2->Text); Result = ldexp(x, y); Edit3->Text = FloatToStr(Result); } //--------------------------------------------------------------------------- The ldexp() function works on double-precision numbers while the ldexpl() uses long doubles.
Extended __fastcall Ldexp(Extended X, int P); The VCL's Ldexp() function is used to calculate a number that is derived from a known mantissa and an exponent numbers. To perform this calculation, the function uses the formula: Result = X * 2P //--------------------------------------------------------------------------- void __fastcall TForm1::Button1Click(TObject *Sender) { float Source = 450.04; float Exp = 10.25; double Result = Ldexp(Source, Exp); Edit1->Text = Result; } //--------------------------------------------------------------------------- |
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