C frexp() function

C frexp() function - Extract mantissa and exponent from a double precision number

Syntax:

double frexp(double x, int *exponent)

The frexp() function is used to break down the floating-point value x into a term m for the mantissa and another term n for the exponent.

Parameters:

Return value from frexp()

• Returns the mantissa term m.
• If x is 0, frexp() returns 0 for both the mantissa and exponent. The mantissa has the same sign as the argument x.

Example: frexp() function

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

#include <math.h>
#include <stdio.h>

int main( void )
{
   double x, y;
   int n;

   x = 16.4;
   y = frexp( x, &n );
   printf( "frexp( %f, &n ) = %f, n = %d\n", x, y, n );
   x = 25.9;
   y = frexp( x, &n );
   printf( "frexp( %f, &n ) = %f, n = %d\n", x, y, n );
   x = 100.2;
   y = frexp( x, &n );
   printf( "frexp( %f, &n ) = %f, n = %d\n", x, y, n );
}

Output:

frexp( 16.400000, &n ) = 0.512500, n = 5
frexp( 25.900000, &n ) = 0.809375, n = 5
frexp( 100.200000, &n ) = 0.782813, n = 7

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