C++ sin()

The sin() function in C++ returns the sine of an angle (argument) given in radians.

This function is defined in <cmath> header file.


[Mathematics] sin x = sin(x) [In C++ Programming]

sin() prototype (As of C++ 11 standard)

double sin(double x);
float sin(float x);
long double sin(long double x);
double sin (T x); // For integral type

sin() Parameters

The sin() function takes a single mandatory argument in radians.


sin() Return value

The sin() function returns the value in the range of [-1, 1]. The returned value is either in double, float, or long double.


Example 1: How sin() works in C++?

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
  double x = 0.439203, result;
  
  result = sin(x);
  cout << "sin(x) = " << result << endl;
  
  double xDegrees = 90.0;
  
  // converting degrees to radians
  x = xDegrees*3.14159/180;
  result = sin(x);
  
  cout << "sin(x) = " << result << endl;

  return 0;
}

When you run the program, the output will be:

sin(x) = 0.425218
sin(x) = 1

Example 2: sin() function with integral type

#include <iostream>
#include <cmath>
using namespace std;

int main()
{
  int x = -1;
  double result;

  result = sin(x);
  cout << "sin(x) = " << result << endl;
  
  return 0;
}

When you run the program, the output will be:

sin(x) = -0.841471