理由：没有取模运算的测试点，以下代码可以AC

#include <iostream>
using namespace std;
int main() {
	int a, b;
	char op;
	cin >> a >> op >> b;
	if (op == '+') {
		cout << a + b;
	}
	else if (op == '-') {
		cout << a - b;
	}
	else if (op == '*') {
		cout << a * b;
	}
	else if (op == '/') {
		cout << a / b;
	}
	return 0;
}

hack:
in:

78%13

out:

0