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C Language: frexp function
(Split into Fraction and Exponent)

In the C Programming Language, the frexp function splits a floating-point value into a fraction and an exponent. The fraction is returned by the frexp function and the exponent is stored in the exp variable.

Syntax

The syntax for the frexp function in the C Language is:

double frexp(double value, int *exp);

Parameters or Arguments

value

The floating-point value to split into a fraction and an exponent.

exp

A pointer to an integer variable where the exponent will be stored.

Returns

The frexp function returns the fractional part of value based on the equation: fraction x 2 ^exponent

The fraction must be greater than or equal to 0.5 and less than 1, or the fraction must be equal to 0.

Required Header

In the C Language, the required header for the frexp function is:

#include <math.h>

Applies To

In the C Language, the frexp function can be used in the following versions:

• ANSI/ISO 9899-1990

frexp Example

/* Example using frexp by TechOnTheNet.com */

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

int main(int argc, const char * argv[])
{
    /* Define temporary variables */
    double value;
    int e;
    double f;

    /* Assign the value we will find the exp of */
    value = 1.5;

    /* Calculate the fraction and exponential of the value */
    f = frexp(value, &e);

    /* Display the result of the calculation */
    printf("The Fraction and Exponential of %f are %f and %d\n", value, f, e);

    return 0;
}

When compiled and run, this application will output:

The Fraction and Exponential of 1.500000 are 0.750000 and 1

Similar Functions

Other C functions that are similar to the frexp function:

• ldexp function <math.h>

See Also

Other C functions that are noteworthy when dealing with the frexp function:

• modf function <math.h>