What should main() return in C and C++?

In both C and C++, the main function should (and by standard, must) return an int value. This return value informs the environment (e.g., the operating system or calling process) about the program’s exit status:

• return 0; traditionally indicates successful execution.
• Non-zero returns often indicate some kind of failure or error.
• In C++, if you omit an explicit return statement from main, many compilers automatically insert return 0; for you (though it’s still best practice to write it explicitly).

Examples

int main() {
    // ... your code ...
    return 0; // signals success
}

// or, with arguments
int main(int argc, char *argv[]) {
    // ... your code ...
    return someErrorCode ? 1 : 0;
}

Recommended Resources

If you’re interested in more foundational knowledge or prepping for coding interviews, here are two recommended courses from DesignGurus.io:

1. Grokking Data Structures & Algorithms for Coding Interviews – Strengthen your base in memory management, arrays, lists, and more.
2. Grokking the Coding Interview: Patterns for Coding Questions – Learn key patterns repeatedly tested in interviews, helping you craft efficient solutions under time pressure.

By consistently returning an appropriate integer code from main, you adhere to the language standards and provide valuable feedback to the calling environment regarding your program’s success or failure.