ERROR: '::main' must return 'int'

Question

This my main function:

void main(int argc, char **argv)
{
    if (argc >= 4)
    {
        ProcessScheduler *processScheduler;
        std::cout <<
            "Running algorithm: " << argv[2] <<
            "\nWith a CSP of: " << argv[3] <<
            "\nFilename: " << argv[1] <<
            std::endl << std::endl;

        if (argc == 4)
        {
            processScheduler = new ProcessScheduler(
                argv[2],
                atoi(argv[3])
            );
        }
        else
        {
            processScheduler = new ProcessScheduler(
                argv[2],
                atoi(argv[3]),
                atoi(argv[4]),
                atoi(argv[5])
            );
        }
        processScheduler -> LoadFile(argv[1]);
        processScheduler -> RunProcesses();

        GanntChart ganntChart(*processScheduler);
        ganntChart.DisplayChart();
        ganntChart.DisplayTable();
        ganntChart.DisplaySummary();

        system("pause");

        delete processScheduler;
    }
    else
    {
        PrintUsage();
    }
}

The error I get when I compile is this:

Application.cpp:41:32: error: '::main' must return 'int'

It's a void function how can I return int and how do I fix it?

Change the signature to `int`. – Eli Sadoff Nov 02 '16 at 14:06 — Eli Sadoff, Nov 02 '16 at 14:06
See http://stackoverflow.com/q/3652182/10077 – Fred Larson Nov 02 '16 at 14:07 — Fred Larson, Nov 02 '16 at 14:07
What's unclear about that error message for you? – πάντα ῥεῖ Nov 02 '16 at 14:21 — πάντα ῥεῖ, Nov 02 '16 at 14:21

Michael · Accepted Answer · 2016-11-02T14:13:09.773

9

Try doing this:

int main(int argc, char **argv)
{
    // Code goes here

    return 0;
}

The return 0; returns a 0 to the operating system which means that the program executed successfully.

edited Nov 02 '16 at 14:13

answered Nov 02 '16 at 14:07

Michael

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5

The `return 0;` is implied in C++, and unnecessary. – molbdnilo Nov 02 '16 at 14:14
1

Yes I agree. It is there for convention and is good practice to include so there's no ambiguity. – Michael Nov 02 '16 at 14:15
Thanks, I wanted to have void main and return nothing but I guess it has to be int. after changing void to int that did solve the error – SPLASH Nov 02 '16 at 16:17
1

@Michael this is not the solution. – roottraveller Sep 11 '17 at 11:33
@roottraveller can you provide some insight as to why it isn't? – Michael Sep 12 '17 at 19:35

score 7 · Answer 2 · edited Sep 13 '17 at 10:03

7

C++ requires main() to be of type int.

edited Sep 13 '17 at 10:03

roottraveller

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answered Nov 02 '16 at 14:18

Nick Pavini

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Thanks, I didn't know about that. I thought you could have void main – SPLASH Nov 02 '16 at 16:20
@Nick Pavini, do you have any documentation? please share with us. – roottraveller Sep 11 '17 at 11:33
1

conflict to this answer - https://stackoverflow.com/questions/2890848/can-main-function-return-double – roottraveller Sep 11 '17 at 11:35

score 1 · Answer 3 · answered Nov 02 '16 at 14:14

1

Function is declared as int main(..);, so change your void return value to int, and return 0 at the end of the main function.

answered Nov 02 '16 at 14:14

renonsz

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ERROR: '::main' must return 'int'

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