practice_1.c

#include <stdio.h>

int main(void) {
    char s[6]={};
    int i=0;
    do{
        if(i<5)
            scanf("%c",&s[i++]);
        else break;
    }while((s[i-1] != 'y'&&s[i-1]!='Y'&&s[i-1]!='n'&&s[i-1]!='N'));
    return 0;
}