Question

我正在尝试从数组调用函数Greeting。有人可以给我一个提示或指导我在线观看视频或阅读。感谢

int Greeting()
{
    printf("Hello, World!\n");
    return 0;
}

int process[]={0,0,&Greeting,0,0,0};

int main()
{
    process[2];
    return 0;
}

Answer 1

您的process是int的数组。你需要使它成为一个函数指针数组。

int (*process[])(void) = {0, 0, Greeting, 0, 0, 0};

然后间接调用该函数

process[2]();

Answer 2

一个简单的例子，其中首先在结构中创建两个函数指针，然后创建三个函数。使用要调用的函数初始化函数指针，然后传递参数以完成工作。

#include <stdio.h>

typedef struct
{
    /* Any function who take two int parameters and returns int can be pointed by this function pointer. */
    int (*function_name)(int a, int b);

    /* This can point to all functions having int argument and void return type */
    void (*print_fn)(int sum);

} FN_GROUP;

int add(int a, int b)
{
    return (a + b);
}

int subtract(int a, int b)
{
    return (a - b);
}

void show(int num)
{
   printf("Result:%d\r\n", num);
}

int main()
{
    int num1 = 20;
    int num2 = 10;
    int result = 0;   
    FN_GROUP group;

    /* Initialize the pointers with add() and show() functions. */    
    group.function_name = &add;
    group.print_fn = &show;

    /* Now call these functions. */
    result = group.function_name(num1, num2);
    group.print_fn(result);

    /* Initialize the pointers with subtract(). */        
    group.function_name = &subtract;

    /* Now call these functions again */
    result = group.function_name(num1, num2);
    group.print_fn(result);

    return (0);
}

从C中的数组调用函数

2 个答案: