#include <iostream>
#include "math.h"
using namespace std;
float deg2rad(float deg)
{
      return deg * M_PI / 180.0;
}
float rad2deg(float rad)
{
	return rad * 180.0 / M_PI;
}
int main()
{
    float tala;
    int op = -1;
    while ((op < 0) || (op > 2))
    {
          cout << "0. to exit the program." << endl;
          cout << "1. for radians to degrees." << endl;
          cout << "2. for degrees to radians." << endl;
          cout << "Type in your selection: ";
          cin >> op;
          cout << endl;
    }
    if (op == 1)
    {
        cout << "Type in a nr. in radians: ";
        cin >> tala;
        cout << tala << " radians are " << rad2deg(tala) << " in degrees." << endl;
    }
    else if (op == 2)
    {
        cout << "Type in a nr. in degrees: ";
        cin >> tala;
        cout << tala << " degrees are " << deg2rad(tala) << " in radians." << endl;
    }
    
    if (op == 0)
       return 0;
    cout << endl;
    system("pause");
    return 0;
}