c语言怎么实现一个计算器

在C语言中实现一个基本的计算器，可以采用函数或结构体结合控制结构来完成。这里给出一个简单的命令行界面计算器示例，它支持加减乘除运算：

#include <stdio.h>

// 定义计算函数
int calculate(int num1, int num2, char operator) {
    switch (operator) {
        case '+':
            return num1 + num2;
        case '-':
            return num1 - num2;
        case '*':
            return num1 * num2;
        case '/':
            if (num2 != 0)
                return num1 / num2;
            else
                printf("Error! Division by zero is not allowed.\n");
            return 0; // 避免程序继续执行错误结果
        default:
            printf("Invalid operator.\n");
            return 0;
    }
}

int main() {
    int num1, num2;
    char operator;

    printf("Enter the first number: ");
    scanf("%d", &num1);
    printf("Enter the second number: ");
    scanf("%d", &num2);
    printf("Enter an operator (+, -, *, /): ");
    scanf(" %c", &operator);

    int result = calculate(num1, num2, operator);
    if (result) {
        printf("The result is: %d\n", result);
    }

    return 0;
}