計算機のプログラムを作りました

#include <stdio.h>
void main()
{
int a;
int b;
char operater;

printf("input number : ");
scanf("%d",&a);


do{

printf("input number : ");
scanf("%d",&b);
printf("input operater : ");
scanf("%c",&operater);
switch(operater){
case '+' : a = a + b; printf("%d\n",a); break;
case '-' : a = a - b; printf("%d\n",a); break;
case '*' : a = a * b; printf("%d\n",a); break;
case '/' : a = a / b; printf("%d\n",a); break;
default : printf("such an operater does not exist!\n"); break;
}
}while(1);
}