#include <iostream>

#include <cmath>


int main() {

  // Compute the square root of a number

  double num = 4.0;

  double sqrt_num = sqrt(num);

  std::cout << "The square root of " << num << " is " << sqrt_num << std::endl;


  // Compute the sine of an angle in radians

  double angle = M_PI / 4;  // M_PI is a predefined constant for pi

  double sin_angle = sin(angle);

  std::cout << "The sine of " << angle << " radians is " << sin_angle << std::endl;


  // Compute the absolute value of a number

  double neg_num = -5.0;

  double abs_num = abs(neg_num);

  std::cout << "The absolute value of " << neg_num << " is " << abs_num << std::endl;


  // Round a number up to the nearest integer

  double decimal = 3.7;

  int rounded_up = ceil(decimal);

  std::cout << "The number " << decimal << " rounded up is " << rounded_up << std::endl;


  return 0;

}

output :

The square root of 4 is 2
The sine of 0.785398 radians is 0.7071067811865475
The absolute value of -5 is 5
The number 3.7 rounded up is 4