答案:#include <iostream>Int main() { double num1, num2; char op; std::cout << "Enter first number: "; std::cin >> num1; std::cout << "Enter an operator (+, -, *, /): "; std::cin >> op; std::cout << "Enter second number: "; std::cin >> num2; double result; switch (op) { case '+': result = num1 + num2; break; case '-': result = num1 - num2; break; case '*': result = num1 * num2; break; case '/': result = num1 / num2; break; default: std::cout << "Invalid operator!"; return 0; } std::cout << "Result: " << result << std::endl; return 0;}