trig in cpp

_trig.cc

#define _USE_MATH_DEFINES
#include <cmath>
#include <iostream>
#include <cstdio>


using namespace std;

void trig(double angle, double *sine, double *cosine, double *tangent)
{
  angle = angle * M_PI / 180; 

  *sine=sin(angle);
  *cosine=cos(angle);
  *tangent=tan(angle);
}

int main ( void )
{

  double sine,cosine,tangent;
  double angle = 180; 
  trig(angle, &sine, &cosine, &tangent);
  cout << angle << endl;
  cout << "sin: " << sine << endl;
  cout << "cos: " << cosine << endl;
  cout << "tan: " << tangent << endl;
  printf("%3.1f %3.1f %3.1f\n",sine,cosine,tangent);

}

Makefile

trig: trig.cc
	g++ -o trig trig.cc -Wall -Wextra -pipe -lm