Sams Teach Yourself C in 21 Days

abs() int abs(int x) Return the absolute

labs()long labs(long x)

value of their arguments.

floor() double floor(double x) Returns the largest integer not greater

than its argument. For example,

floor(4.5)returns4.0, and

floor(-4.5)returns-5.0.

modf() double modf(double x, Splitsxinto integral and fractional

double *y) parts, each with the same sign as x.

The fractional part is returned by the

function, and the integral part is

assigned to *y.

pow() double pow(double x, Returnsxy. An error occurs if x == 0

double y) andy <= 0, or if x < 0andyis not

an integer.

fmod() double fmod(double x, Returns the floating-point remainder

double y) ofx/y, with the same sign as x. The

function returns 0 ifx == 0.

A Demonstration of the Math Functions ......................................................

An entire book could be filled with programs demonstrating all of the math functions.

Listing 19.1 contains a single program that demonstrates several of these functions.

LISTING19.1 math.c. Using the C library math functions

1: /* Demonstrates some of C’s math functions */

2:

3: #include <stdio.h>

4: #include <math.h>

5:

6: int main( void )

7: {

8:

9: double x;

10:

11: printf(“Enter a number: “);

12: scanf( “%lf”, &x);

13:

14: printf(“\n\nOriginal value: %lf”, x);

15:

536 Day 19

Function Prototype Description

INPUT

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