Question

How to clear the scanf input buffer in C

Answer 1

#include <stdio.h>

int main()
{
    int number;

    while (1) {
        printf("Choose 1, 2, 3 or 4: ");

        if (scanf("%d", &number) != 1) {
            // clear the scanf input buffer
            while ((number = getchar()) != '\n' && number != EOF) {} // fflush(stdin);
        }

        if (number == 1 || number == 2 || number == 3 || number == 4) {
            break;
        }

        puts("Invalid selection, choose again.");
    }

    printf("You choose: %d\n", number);
}



/*
run:

Choose 1, 2, 3 or 4: w
Invalid selection, choose again.
Choose 1, 2, 3 or 4: x
Invalid selection, choose again.
Choose 1, 2, 3 or 4: 7
Invalid selection, choose again.
Choose 1, 2, 3 or 4: 3
You choose: 3

*/

 

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