C Language: atan2 function(Arc Tangent of Quotient)

C Programming allows us to perform mathematical operations through the functions defined in header file. The header file contains various methods for performing mathematical operations such as sqrt(), pow(), ceil(), floor() etc.

C Math Functions

In the C Programming Language, the atan2 function returns the arc tangent of y / x.

Syntax

The syntax for the atan2 function in the C Language is:




double atan2(double y, double x);



Parameters or Arguments

The parameter when calculating the arc tangent of y / x.

The parameter when calculating the arc tangent of y / x.

Returns

The atan2 function returns the arc tangent of y / x. It will return a value between -π and π. If x and y are both equal to 0, the atan2 function will return a domain error.

Required Header

In the C Language, the required header for the atan2 function is:




#include <math.h>



Applies To

In the C Language, the atan2 function can be used in the following versions:

  • ANSI/ISO 9899-1990
  • atan2 Example



    
    /* Example using atan2 by c programming */
    
    #include <stdio.h>
    #include <math.h>
    
    int main(int argc, const char * argv[])
    {
        /* Define temporary variables */
        double value1, value2;
        double result;
    
        /* Assign the two values we will find the atan2 of */
        value1 = 0.5;
        value2 = -0.5;
    
        /* Calculate the Arc Tangent of value1 and value2 */
        result = atan2(value1, value2);
    
        /* Display the result of the calculation */
        printf("The Arc Tangent of %f and %f is %f\n", value1, value2, result);
    
        return 0;
    }
    
    


    When compiled and run, this application will output:

    The Arc Tangent of 0.500000 and -0.500000 is 2.356194




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