Control reaches end of non-void function c++

Question

Problem:

I am trying to make a program that will convert the temperature from Celcius to Fahrenheit and vice-versa.

The sample code is attached below:

#include <iostream>

using namespace std;

void dialouge();
int c2f();
int f2c();

int c2f()
{
    int c;
    int choice;
    cout << "Please enter the degree in Celsius: \n";
    cout << ":.: ";
    cin >> c;
    cout << ":F: " << c * 1.8 + 32 << endl;
    cin.get();

    cout << "Convert another degree?\n";
    cout << "1. Yes.\n";
    cout << "2. No.\n";
    cout << ":.: ";
    cin >> choice;

    if (choice == 1)
    {
        dialouge();
    }

    else if (choice == 2)
    {
        return 0;
    }
}

int f2c()
{
    int f;
    int choice;
    cout << "Please enter the degree in Fahrenheit: \n";
    cout << ":.: ";
    cin >> f;
    cout << ":C: " << f - 32 * 5 / 9 << endl;
    cin.get();

    cout << "Convert another degree?\n";
    cout << "1. Yes.\n";
    cout << "2. No.\n";
    cout << ":.: ";
    cin >> choice;

    if (choice == 1)
    {
        dialouge();
    }

    else if (choice == 2)
    {
        return 0;
    }
}

void dialouge()
{
    int choice;
    cout << "Please choose your desired option:-\n";
    cout << "1. Celsius to Fahrenhite.\n";
    cout << "2. Fahrenhite to Celsius.\n";
    cout << ":.: ";
    cin >> choice;

    if (choice == 1)
    {
        c2f();
    }

    else if (choice == 2)
    {
        f2c();
    }
}

int main()
{
    cout << "This program allows you to convert from Celsius to Fahrenheit and vice versa.\n";
    dialouge();

}

 

But the problem is: When I compile it, CodeBlocks keeps giving me the following warning:
int f2c(): control reaches end of non-void function
int c2f(): control reaches end of non-void function

what does it mean? and if there is anything wrong that I haven't noticed, please point it out.

Answer 1

The compiler throws back the error because the functions f2c and c2f do not return values on all control paths.

I hope this will help you:

int func(int choice) // This function will return an integer value
{
    if(choice == 1)
    {
        return 1;  // If choice is not 1, then this code is never executed and the function will not return an int
    }
}

int func2(int choice)
{
    if(choice == 1)
    {
        return 1;  // If choice is 1, then 1 is returned
    }
    return 0;  //If choice is not 1, then 0 is returned, so every possible control path returns something
}

Thanks