C++ Unexpected number output

Question

EDIT: Fixed the problem thanks to advice from below. Changed the return type of evaluation() from an int to a void.

I'm learning how to use classes, and I'm experiencing a problem. I keep getting an output that says:

0
They are not equal.
4469696

Where is that last number coming from? It should be somewhere after the line

std::cout << Thing.evaluation(Thing.getValue()) << std::endl;

but I don't see anything that could possibly be outputting that value. Is it memory leakage?

#include <iostream>
#include <conio.h>

class classTest
{
      public:
             int equivalency(int x, int y)
             {
                 if (x == y)
                 {
                       value = 1;
                 } else
                 {
                       value = 0;      
                 }
             }

             int evaluation(int z)
             {
                 if (z == 0)
                 {
                       std::cout << "They are not equal." << std::endl;
                 } else 
                  {
                        std::cout << "They are equal." << std::endl;
                  }
             }

             int getValue()
             {
                 return value;
             }

       private:
              int value;
};

int main()
{
    int a = 0, b = 0;
    classTest Thing;

    std::cout << "Enter two numbers for comparison." << std::endl;
    std::cin >> a >> b;

    Thing.equivalency(a, b);

    std::cout << Thing.getValue() << std::endl;

    std::cout << Thing.evaluation(Thing.getValue()) << std::endl;

    getch();
    return 0;
}

Answer 1

In evaluation() you print the expected messages. Then you don't return anything from this function although it is declared to return int , ie, you get undefined behavior. Further more, you actually point the random result since you output the result of the call:

std::cout << Thing.evaluation(Thing.getValue()) << std::endl;

BTW, don't use std::endl ! If you want a newline, use '\\n' , if you want to flush the buffer use std::flush . Unnecessary use of std::endl is a relatively frequent source of major performance problems.