atan
The C++ atan() function returns the inverse tangent of an angle in radian.It is defined in <cmath> header file.
Syntax
atan(x)
Parameters
The atan() function takes a one argument. It can be positive, negative, or zero.
Return value
The atan() function returns the value in the range of [-π/2, π/2].
atan() prototype [As of C++ 11 standard]
double atan(double x); float atan(float x); long double atan(long double x); double atan (T x); // For integral type
arc tan
Example 1: C++ atan()
#include <stdio.h> #include <math.h> #define PI 3.14159265 int main () { double param, result; param = 4.4; result = atan(param) * 180 / PI; printf ("The arc tangent of %f is %f degrees\n", param, result ); return 0; }
Output
The arc tangent of 4.400000 is 77.195734 degrees
atan function
Example 2
#include <stdio.h> #include <math.h> #define PI 3.14159265 int main () { double param, result; param = 0.1; result = atan(param) * 180 / PI; printf ("The arc tangent of %f is %f degrees\n", param, result ); return 0; }
Output
The arc tangent of 0.100000 is 5.710593 degrees