CODEWITHSUNDEEP
cwhile-loop
Arnold Hotz
Arnold Hotz

Reputation: 189

While loop not waiting for input with scanf("%d")

I have a while loop that prints a prompt for an integer. I want to error check for when the user enters a char, like 'a'. However, when I type 'a', it prints "Enter the seed: Seed must be an integer value, please try again" forever.

int getSeed() {
    int scanned, seed;

    while (scanned == 0) {
       printf("Enter the seed: ");
       scanned = scanf("%d", &seed);
       if (scanned == 0) {
          printf("Seed must be an integer, try again\n");
       }
    }
    return seed;
}

How do I get this to print

Enter the seed: a Seed must be an integer, try again Enter the seed:

Thanks.

EDIT: Solved it, I added getchar(); after the scanf.

Upvotes: 1

Views: 501

Answers (1)

Ali Seyedi
Ali Seyedi

Reputation: 1817

scanf checks your input character and finds out that it does not match the conversion specifier, so it puts it back in the input stream.
Then in your while loop in your code reaches to scanf again, and the above process occurs again (since the a you've written in input stream is still there)

So a better solution would be reading it as a character (or string) and then converting that into an integer.

Upvotes: 0

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