一个RE，明明外面能运行……题解全是C++我有点想直接去学又怕基础不够

#include<stdio.h> 
int main()
{
	int x,y;
	char z;
	scanf("%d %d %c",&x,&y,&z); 
	if(z=='+')
	printf("%d",x+y);
	if(z=='-')
	printf("%d",x-y);
	if(z=='*')
	printf("%d",x*y);
	if(z=='/')
	printf("%d",x/y);
	if(y==0&&z=='/')
	printf("Divided by zero!");
	if(z!='+'&&z!='-'&&z!='*'&&z!='/')
	printf("Invalid operator!");
	return 0;
}