Usage and Example of C Library Function frexp()

C Standard Library - <math.h>

C Library Function double frexp(double x, int *exponent) Split the floating-point number x into the mantissa and exponent. The return value is the mantissa, and the exponent is stored in exponent . The obtained value is x = mantissa * 2 ^ exponent.

Declaration

Below is the declaration of the frexp() function.

double frexp(double x, int　*exponent)

Parameter

• x 　-- The floating-point value to be calculated.

• exponent 　-- A pointer to an object that stores the value of the exponent.

Return Value

The function returns the normalized decimal. If the parameter x is not zero, the normalized decimal is the square of x, and its absolute value range is from 1/2Contains) to 1If x is zero, the normalized decimal is zero, and zero is stored in exp.

Online Example

The following example demonstrates the usage of the frexp() function.

#include <stdio.h>
#include <math.h>
int main ()
{
　　　double x =　2048, fraction;
　　　int e;
　　　
　　　fraction = frexp(x, &e);
　　　printf("x = %."2lf = %.2lf　*　2^%d\n", x, fraction, e);
　　　
　　　return(0);
}

Let's compile and run the above program, which will produce the following result:

x =　2048.00 = 0.50　*　2^12

C Standard Library - <math.h>