C++ Some variables “used uninitialized in this function”. Why?

Question

This is my code:

#include 
using namespace std;

void input_function(int hour, int minutes);
void calcuation(int hour, int minutes, char meri         


        

Answer 1

Your input_function should pass by reference.
If you pass by value only, it would not affect anything.

  #include 
    using namespace std;

    void input_function(int& hour, int& minutes);
    void calcuation(int hour, int minutes, char meridien);
    void output_function(int hour, int minutes, char meridien);

    int main ()
    {
      int hour, minutes;
      char answer, meridien;

      do
        {
          input_function(hour, minutes);
          calcuation(hour, minutes, meridien);
          output_function(hour, minutes, meridien);


          cout << "Would you like to try again? (Y/N)\n";
          cin >> answer;

        } while(answer == 'Y' || answer == 'y');

      cout <<"Goodbye\n";

      return 0;
    }

    void input_function(int& hour, int& minutes)
    {
      cout << "Enter the hour in 24 hour notation: (Ex. 23)\n";
      cin >> hour;

      cout << "Enter the minutes:\n";
      cin >> minutes;
    }

    void calcuation(int hour, int minutes, char meridien)
    {
      if (hour > 12)
        {
          hour = hour - 12;
          meridien = 'P';
        }
      else 
        {
          meridien = 'A';
        }
    }

    void output_function(int hour, int minutes, char meridien)
    {
      cout << "Your time in 12 hour notation is:\n";
      cout << hour << ":" << minutes << endl;

      if (meridien == 'P')
        cout << "P.M.\n";

      else 
        cout << "A.M\n";
    }