Question

I get the following warning when I try to compile the code:

program141.c:13:5: warning: format ‘%i’ expects argument of type ‘int *’, but argument 2 has type ‘enum month *’ [-Wformat]

// Program to print the number of days in a month

#include <stdio.h>

int main (void)
{
    enum month { january = 1, february, march, april, may, june,
         july, august, september, october, november, december };
    enum month aMonth;
    int        days;

    printf ("Enter month number: ");
    scanf ("%i", &aMonth);

    switch (aMonth) {
    case january:
    case march:
    case may:
    case july:
    case august:
    case october:
    case december:
        days = 31;
        break;
    case april:
    case june:
    case september:
    case november:
        days = 30;
        break;
    case february:
        days = 28;
        break;
    default:
        printf ("bad month number\n");
        days = 0;
        break;
    }

    if ( days != 0 )
    printf ("Number of days is %i\n", days);

    if ( aMonth == february )
    printf ("...or 29 if it's a leap year\n");

    return 0;
}

This code is from a book I’m reading.

How do I fix this warning?

Answer 1

Try with:

scanf ("%u", &aMonth);