C++ Unexpected number output - c++

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, i.e., 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.