Thread: Days of the week program

Hello!

I am stuck on this program I have to write for the days of the week. The days of the week is in a string array, and the program asks the user for a number between 1 and 7. The program is then supposed to spit out the corresponding day of the week. There also needs to be an error message if the user enters anything besides 1-7. This is what I got, and it keeps telling me it's Sunday no matter what I enter! Could anyone please lend me a hand to find out what is wrong here?

Code:

# include <stdio.h>

int main()
{
        int day;
        char *weekday[7] =
        {
           "Sunday",
           "Monday",
           "Tuesday",
           "Wednesday",
           "Thursday",
           "Friday",
           "Saturday"
        };

        printf ("Enter number between 1-7: ");
        scanf ("%d", &day);
        printf("\nThe day of the week is:\n\n");

        if ((day=1))
        {
                printf("%s", weekday[0]);
        }

        else if ((day=2))
        {
                 printf("%s", weekday[1]);
        }

        else if ((day=3))
        {
                printf ("%s", weekday[2]);
        }

        else if ((day=4))
        {
                 printf ("%s", weekday[3]);
        }

        else if ((day=5))
        {
                printf ("%s", weekday[4]);
        }

        else if ((day=6))
        {
                printf ("%s", weekday[5]);
        }

        else if ((day=7))
        {
                printf ("%s", weekday[6]);
        }

        else
        {
                printf("Error");
        }

        return 0;
}

Thank you!

You need to use == to compare values, not =. A single = is assignment. When you do if(day = 1) then you're assigning 1 to day, and the result is if(1), which is always true. I presume you put an extra pair of parentheses around the statements because your compiler was complaining. It was right! You don't want assignment here.

But there is a much easier way to accomplish this: first, make sure day is between 1 and 7. Then you can simply do weekday[day - 1].

Thank you! And yes, the reason I put the double parenthesis there is because the compiler wasn't happy. But, for some reason, I thought that would fix the problem too (I thought it was either use == OR ((...)) for some reason). I have to go to class now, but I will fix this afterwards. I will post if I have any more complications. Thank you again!

Referring to message #1... everything from line 21 to line 55 can be reduced to...

Code:

printf("%s",weekday[day - 1]);

Why day - 1? Because it is common for people to enter days from 1 to 7... but C arrays actually start at 0 giving you a range from 0 to 6... the -1 merely offsets the range to give you the right day.

A matter of personal choice I suppose, but when dealing with constants or literals,

Code:

if( 1 = day )

will never compile and you'll hopefully be pointed directly to the problem.

Code:

if( day = 1 )

On the other hand, this second one will compile, and depending on your compiler or warning settings, may not complain at all.