Thread: passing variables from main to another function

Well 'getMonth' from the sound of it, shouldn't be passed anything, especially considering that you're returning one already. Just do:

Code:

int main( void )
{
    unsigned int month;

    month = getMonth( ); /* call your function, assing the return to 'month' */

    ... stuff ...

    return 0;
}

If you want to pass it, and have that updated, then you'll need to pass a pointer to it:

Code:

void getMonth( unsigned int *month )
{
    ...fill in month...
}

int main( void )
{
    unsigned int month;

    getMonth( &month );

    ... stuff ...

    return 0;
}

So in short:
1 - Return it and assign the returned value.
2 - Pass a pointer to it and modify that.

However, if all you want to do is pass the value around, and not change it in the function, then simply pass it like any other variable:

Code:

void printMonth( unsigned int month )
{
    ... print out the month you pass ...
}

int main( void )
{
    unsigned int month;

    ... stuff ...

    printMonth( month );

    return 0;
}

Quzah.

Originally Posted by quzah

If you want to pass it, and have that updated, then you'll need to pass a pointer to it:

Code:

void getMonth( unsigned int *month )
{
    ...fill in month...
}

int main( void )
{
    unsigned int month;

    getMonth( &month );

    ... stuff ...

    return 0;
}

I disagree -- at least from a 'purist' standpoint. If passing back a single value, IMO it should be passed back via return rather than the param list.
Then the calling function can explicitly change the value if need be:

Code:

unsigned int getMonth( unsigned int month )
{
    ...fill in month...
    return newmonth;
}

int main( void )
{
    unsigned int month;

    // function does it's thing and returns the new month
    month = getMonth( month ); 

    ... stuff ...

    return 0;
}