Linux C library functions encyclopedia: Mathematical Functions

1.abs (Calculate the absolute value of the integer number)

Related functions:

Labs, Fabs

Table header file:

#include <math.h>

To define a function:

int abs (int j)

Function Description:

ABS () is used to calculate the absolute value of the parameter J, and then return the result.

return value:

Returns the absolute result of the parameter J.

Example:

#include <stdio.h> 
#include <math.h> 
main () 
    { 
        int answer; 
        Answer = ABS ( -12); 
        printf ("|-12| =%d\n ", answer); 
    }

2.acos (Take the inverse cosine function value)

Related functions:

ASIN, ATAN, atan2, cos, sin, tan

Table header file:

#include <math.h>

To define a function:

Double ACOs (double x);

Function Description:

ACOs () is used to calculate the inverse cosine of the parameter x, and then returns the result. The parameter x range is between 1 and 1 and will fail if it exceeds this range.

return value:

Returns the calculated result between 0 and pi, in radians, in radians in the function library.

Error code:

Edom parameter x is out of range.

Example:

#include <stdio.h> 
#include <math.h> 
main () 
    { 
        double angle; 
        Angle = ACOs (0.5); 
        printf ("angle =%f\n", angle); 
    }