This function is defined in <cmath> header file.
[Mathematics] tan-1(y/x) = atan2(y, x) [In C++ Programming]
atan2() prototype [As of C++ 11 standard]
double atan2(double y, double x); float atan2(float y, float x); long double atan2(long double y, long double x); double atan2(Type1 y, Type2 x); // For combinations of arithmetic types.
atan2() Parameters
The function atan2() takes two arguments: x-coordinate and y-coordinate.
- x - this value represents the proportion of the x-coordinate.
- y - this value represents the proportion of the y-coordinate.
atan2() Return value
The atan2() function returns the value in the range of [-π, π]. If both x and y are zero, the atan2() function returns 0.
Example 1: How atan2() works with same type of x and y?
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
double x = 10.0, y = -10.0, result;
result = atan2(y, x);
cout << "atan2(y/x) = " << result << " radians" << endl;
cout << "atan2(y/x) = " << result*180/3.141592 << " degrees" << endl;
return 0;
}
When you run the program, the output will be:
atan2(y/x) = -0.785398 radians atan2(y/x) = -45 degrees
Example 2: How atan2() works with different types of x and y?
#include <iostream>
#include <cmath>
#define PI 3.141592654
using namespace std;
int main()
{
double result;
float x = -31.6;
int y = 3;
result = atan2(y, x);
cout << "atan2(y/x) = " << result << " radians" << endl;
// Display result in degrees
cout << "atan2(y/x) = " << result*180/PI << " degrees";
return 0;
}
When you run the program, the output will be:
atan2(y/x) = 3.04694 radians atan2(y/x) = 174.577 degrees