Unusual Behavior observed while calling main() in any other function in c++

Question

I made a simple program to test whether I am able to call main in any other function like we call different functions in other function.

Therefore, I made a program to generate the maximum number by getting input of 3 numbers from the user. For this I made the function containing if else. Surprisingly (especially for me) it worked. I got that I am keep inputting the numbers then I made another variable to control the inputs. I made it to input 3 times. I got answer from bottom to end and 3 answers are generated.

#include <iostream>
using namespace std;
int main();
void max(int a, int b, int c,int p);
int p = 0;
int main()
{
    p++;
    int a, b, c;
    cout << "\n\n";
    cout << "Enter 1st number :\t";
    cin >> a;
    cout << "Enter 2nd number :\t";
    cin >> b;
    cout << "Enter 3rd number :\t";
    cin >> c;
    max(a, b, c, p);
    cout << "\n\n\n";
    system("pause");
    return 0;
}
void max(int a, int b, int c,int p)
{
    if (p < 3) 
    {
        main();
    }
    if (a > b&&a > c)
    {
        cout << a << " is maximum";
    }
    else if (b > a&&b > c)
    {
        cout << b << " is maximum";
    }
    else
    {
        cout << c << " is maximum";
    }
}

The output was as follows: -

Enter 1st number :      12                                                                                              
Enter 2nd number :      14                                                                                              
Enter 3rd number :      15


Enter 1st number :      45                                                                                              
Enter 2nd number :      69                                                                                              
Enter 3rd number :      88  


Enter 1st number :      14                                                                                      
Enter 2nd number :      20                                                                                              
Enter 3rd number :      11                                                                                             
20 is maximum             


                                                                                                                                                                                                                                                                                                                                              Press any key to continue . . .                                                                                         
88 is maximum                                                                                                                                                                                                                                                                                                                                                           



Press any key to continue . . .                                                                                         
15 is maximum                                                                                                                                                                                                                                                                                                                                                           



Press any key to continue . . .  

I don't get the logic behind it. I used Visual Studio 2017 for this.

Answer 1

So I worked a bit on your code, and managed to maybe make it work as you intended it do to. It really wasn't such a big deal. I found a cleaner and easier to read code.

The changes in the code are 1st in the beginning :

#include <iostream>
void max(int a, int b, int c);
int a, b, c;
int main()
{
for(int p = 0; p < 3; p++) {
    std::cout << "\n\n";
    std::cout << "Enter 1st number :\t";
    std::cin >> a;
    std::cout << "Enter 2nd number :\t";
    std::cin >> b;
    std::cout << "Enter 3rd number :\t";
    std::cin >> c;
    max(a, b, c);
    std::cout << "\n\n\n";
}
system("pause");
return 0;
}

You can see I removed the using namespace std; because I really don't like having that, you can add it if you want it it's just my preference. You see I made the whole code repeat in a for loop to remove the calling of the main function, and don't worry many of us have done it too. As you can see I also changes the max() function's parameters The second change in the code is in the last part of the code:

void max(int a, int b, int c)
{

if (a > b&&a > c)
{
    std::cout << a << " is maximum";
}
else if (b > a&&b > c)
{
    std::cout << b << " is maximum";
}
else
{
    std::cout << c << " is maximum";
}
}

Here I just removed the part of the code which calls the main function. And overall it's all that had to change in your code to work.