Материал из C\C++ эксперт
Force user to enter a valid response
#include <stdio.h>
int main(void)
{
int a, b;
char ch;
printf("Do you want to (Choose the first letter):\n");
printf("(A)dd, (S)ubtract, (M)ultiply, or (D)ivide?\n");
do {
printf("Choice: ");
ch = getchar();
} while(ch!="A" && ch!="S" && ch!="M" && ch!="D");
printf("\n");
printf("Enter first number: ");
scanf("%d", &a);
printf("Enter second number: ");
scanf("%d", &b);
if(ch=="A")
printf("%d", a + b);
else if(ch=="S")
printf("%d", a - b);
else if(ch=="M")
printf("%d", a * b);
else if(ch=="D" && b!=0)
printf("%d", a / b);
return 0;
}
