C语言运算符和表达式

#include<stdio.h>
int main( ){
    int n,g,s,b,sum;
	printf("请输入一个三位正整数:");
	scanf("%d",&n);
	b = n / 100;
	s = ( n - g*100) / 10;
	g = n % 10;
	sum = b + g + s ;
	printf("个位：%d，十位：%d，百位：%d \n 总计:%d",g,s,b,sum);
    return 0;
}