C++ atan() function usage and example

C++ Library Function <cmath>

C ++the atan() function.

This function returns the arctangent value of a number (parameter) in radians form in<cmath>header file definition.

[Math] tan-1x = atan(x) [C++];

atan() prototype [from C ++ 11Standard Library]

double atan(double x);
float atan(float x);
long double atan(long double x);
double atan(T x);　//are of integer type

atan() parameters

The atan() function takes a mandatory parameter (can be positive, negative, or zero)

The return value of atan()

The atan() function returns[-π/ 2, π/ 2]values within the range.

Example1: How does atan() work?

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
　　double x =　57.74, result;
　　result = atan(x);
　　
　　cout << "atan(x) = " << result << " radians " << endl;
　　
　　//Output Degrees
　　cout << "atan(x) = " << result*180/3.1415　<< " degrees " << endl;
　　
　　return 0;
}

When running the program, the output is:

atan(x) =　1.55348　radians
atan(x) =　89.0104　degrees

Example2: atan() function with integer type

#include <iostream>
#include <cmath>
#define PI　3.141592654
using namespace std;
int main()
{
　　int x =　14;
　　double result;
　　
　　result = atan(x);
　　
　　cout << "atan(x) = " << result << " radians " << endl;
　　//Output Degrees
　　cout << "atan(x) = " << result*180/3.1415　<< " degrees " << endl;
　　
　　return 0;
}

When running the program, the output is:

atan(x) =　1.49949　radians
atan(x) =　85.9169　degrees

　 C++ Library Function <cmath>