商と余りを出力する形式です。参考にどうぞ。

calc_ex.cpp

#include <iostream>

int main(void) {

	int right_number, left_number;
	char ope;

	std::cin >> left_number >> ope >> right_number;

	std::cout << " = ";

	if (ope == '+') {
		std::cout << left_number + right_number << std::endl;
	}
	else if (ope == '-') {
		std::cout << left_number - right_number << std::endl;
	}
	else if (ope == '*') {
		std::cout << left_number * right_number << std::endl;
	}
	else if (ope == '/') {
		if (right_number == 0) {
			std::cout << "無限です" << std::endl;
		}
		else {
			std::cout << left_number / right_number;
			if (left_number % right_number != 0) {
				std::cout << "余り" << left_number % right_number;
			}
			std::cout << std::endl;
		}
	}
	return 0;
}