编程实现简单的计算器功能，要求用户按如下格式从键盘输入算式： 操作数1 运算符op 操作数2 计算并输出表达式的值，其中算术运算符包括：加（+）、减（-）、乘（*）、除（/）。 **输入格式要求："%d%c%d" 提示信息："Please enter an expression:" **输出格式要求："%d + %d = %d \n" "%d - %d = %d \n" "%d * %d = %d \n" "%d / %d = %d \n" "Division by zero!\n" "Invalid operator! \n" 程序运行示例1如下： Please enter an expression:22+12 22 + 12 = 34 程序运行示例2如下： Please enter an expression:22-12 22 - 12 = 10 程序运行示例3如下： Please enter an expression:22*12 22 * 12 = 264 程序运行示例4如下： Please enter an expression:22/12 22 / 12 = 1 程序运行示例5如下： Please enter an expression:22/0 Division by zero! 程序运行示例6如下： Please enter an expression:22\12 Invalid operator!

下面是 C 语言实现的代码：

#include <stdio.h>

int main() {
    int num1, num2, result;
    char op;
    printf("Please enter an expression:");
    scanf("%d%c%d", &num1, &op, &num2);
    switch(op) {
        case '+':
            result = num1 + num2;
            printf("%d + %d = %d \n", num1, num2, result);
            break;
        case '-':
            result = num1 - num2;
            printf("%d - %d = %d \n", num1, num2, result);
            break;
        case '*':
            result = num1 * num2;
            printf("%d * %d = %d \n", num1, num2, result);
            break;
        case '/':
            if(num2 == 0) {
                printf("Division by zero!\n");
            } else {
                result = num1 / num2;
                printf("%d / %d = %d \n", num1, num2, result);
            }
            break;
        default:
            printf("Invalid operator! \n");
            break;
    }
    return 0;
}