C语言函数指针数组实现计算器功能

int arr[10];
//数组arr的每个元素是int

int* arr[10];
//数组arr的每个元素是int*

int Add(int x, int y)
{
    return x + y;
}
 
int main()
{
    int arr[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int (*p)[10] = &arr; 
    //取出数组的地址，p就是指向数组arr的指针，数组中每个元素类型是int，p就是数组指针
    
    //引出函数指针的问题
    int (*pf)(int, int) = &Add;
    //是一个指向函数的指针 - 存放函数的地址

//函数指针
int (*p)(int, int) = Add;
int (*p)(int, int) = Sub; 
//Add和Sub是函数名，需要传入的两个形参和返回值类型都是int
 
//将上面两个同类型的函数指针放入数组中，得到函数指针数组
int (* arr[2]) (int, int) = {Add, Sub};

#include <stdio.h>
//实现加减乘除
int add(int a, int b)
{
    return a + b;
}
int sub(int a, int b)
{
    return a - b;
}
int sub(int a, int b)
{
    return a * b;
}
int sub(int a, int b)
{
    return a / b;
}
int main()
{
    int x, y;
    int input = 1;
    int ret = 0;
    do
    {
        printf( "***************************\n" );
        printf( "    1:add         2:sub    \n" );
        printf( "    3:mul         4:div    \n" );
        printf( "***************************\n" );
        printf("请选择：");
        scanf("%d", &input);
        switch (input)
        {
        case 1:
                printf("输入操作数: ");
                scanf("%d %d", &x, &y);
                ret = add(x, y);
                printf("ret = %d\n", ret);
                break;
        case 2:
                printf("输入操作数: ");
                scanf("%d %d", &x, &y);
                ret = sub(x, y);
                printf("ret = %d\n", ret);
                break;
        case 3:
                printf("输入操作数: ");
                scanf("%d %d", &x, &y);
                ret = mul(x, y);
                printf("ret = %d\n", ret);
                break;
        case 4:
                printf("输入操作数: ");
                scanf("%d %d", &x, &y);
                ret = div(x, y);
                printf("ret = %d\n", ret);
                break;
        case 0:
                printf("退出程序\n");
                break;
        default:
                printf("退出程序\n");
                break;
        }
    } while (input);
 
    return 0;
} 

#include <stdio.h>
//实现加减乘除
int add(int a, int b)
{
    return a + b;
}
int sub(int a, int b)
{
    return a - b;
}
int sub(int a, int b)
{
    return a * b;
}
int sub(int a, int b)
{
    return a / b;
}
int main()
{
    int x, y;
    int input = 1;
    int ret = 0;
    int (*p[5])(int x, int y) = { 0, add, sub, mul, div };//转移表
    while (input)
    {    
        printf( "***************************\n" );
        printf( "    1:add         2:sub    \n" );
        printf( "    3:mul         4:div    \n" );
        printf( "***************************\n" );
        printf("请选择：");
        scanf("%d", &input);
        if ((input <= 4 && input >= 1))
        {
            printf("输入操作数: ");
            scanf("%d %d", &x, &y);
            ret = (*p[input])(x, y);
        }
        else
        {
            printf( "输入有误\n" );
            printf( "ret = %d\n", ret );
        }
        return 0;
}
       

ret = (*p[input])(x, y);