Do While or while?

Question

I am trying to make my program run only while the user enters Y or y but it only runs once, and even if it isn't Y or y. Input will either be Y, y, N or n

printf("Welcome to the Jumble Puzzle Solver!\n\n");
printf("Would you like to enter a jumbled word?\n");
scanf("%s", &answer);


    do{

    printf("What word would you like scored?\n");
    scanf("%s", &letters);

    strcpy(changeletters, letters);

    recursivepermute(letters, changeletters, checkword, k, dictionary ,max, min);

    printf("Would you like to enter a jumbled word?\n");
    scanf("%s", &answer);

    }while (answer == 'Y' || answer == 'y');

What type is `answer`? Also, the homework tag is deprecated. — chris, Oct 12 '12 at 23:54
possible duplicate of [Test loops at the top or bottom? (while vs. do while)](http://stackoverflow.com/questions/224059/test-loops-at-the-top-or-bottom-while-vs-do-while) — alk, Oct 13 '12 at 12:17

score 1 · Accepted Answer · answered Oct 12 '12 at 23:55

1

do { } while() causes the body to always be executed at least once. If you want the condition checked first, just use while:

// If answer is:
// char answer;

scanf("%c", &answer);
while (answer == 'Y' || answer == 'y')
{
     printf("What word would you like scored?\n");
    // ...

    scanf("%c", &answer);
}

You also need to use scanf("%c" if answer is a char. The %s is to scan a string of characters (ie: char[20]), and would need to be checked differently, using a method like strcmp or similar.

answered Oct 12 '12 at 23:55

Reed Copsey

554,122
78
1,158
1,373

Ok the do while explanation makes a lot of sense. I changed it t %c and made the while loop like this, but even if I enter Y or y it still ends the program. – Ryan Oct 13 '12 at 00:04
@Ryan Check what you're getting in `answer` in a debugger. Is it 'Y' or 'y'? How is `answer` declared? – Reed Copsey Oct 13 '12 at 00:05
Ah figured out my problem. Still had it declared as char answer[2] instead of just char answer. Thank you for all the help! – Ryan Oct 13 '12 at 00:08
@Ryan With a string, you could use `strcmp` to do the check instead of checking against a single character. – Reed Copsey Oct 13 '12 at 00:08

score 0 · Answer 2 · answered Oct 12 '12 at 23:59

0

if you want the user to play the game once and then be asked about playing again then the use of do-while loop is more appropriate. But if you want to give the user the option Not to play the game at all then use the while loop

answered Oct 12 '12 at 23:59

yohannist

4,166
3
35
58

Thank you that explains a lot – Ryan Oct 13 '12 at 00:05

Do While or while?

2 Answers2