Why is scanf() causing infinite loop in this code?

Question

I\'ve a small C-program which just reads numbers from stdin, one at each loop cycle. If the user inputs some NaN, an error should be printed to the console and the input pro

Answer 1

I had similar problem. I solved by only using scanf.

Input "abc123" to see how it works.

#include 
int n, num_ok;
char c;
main() {
    while (1) {
        printf("Input Number: ");
        num_ok = scanf("%d", &n);
        if (num_ok != 1) {
            scanf("%c", &c);
            printf("That wasn't a number: %c\n", c);
        } else {
            printf("The number is: %d\n", n);
        }
    }
}