函数指针数组

#include <stdio.h>
int addition(int i,int j)
{       
        return i + j;
}
int substraction(int i,int j)
{       
        return i - j;
}
int multiplication(int i,int j)
{       
        return i * j;
}
int division(int i,int j)
{       
        return i / j;
}
void menu(void)
{       
        printf("**************************\n");
        printf("**  0 => addition       **\n");
        printf("**  1 => substraction   **\n");
        printf("**  2 => multiplication **\n");
        printf("**  3 => division       **\n");
        printf("**  4 => quit           **\n");
}
int main(void)
{
        // 定义数组，注意这个格式
        int (*actions[])(int,int) = {addition,substraction,multiplication,division};
        int action = 0,max_action_index = sizeof(actions) / sizeof(actions[0]) - 1,left,right,result;
        while(1)
        {
                menu();
                printf("Enter your action:");
                scanf("%d",&action);
                // 清空输出缓冲
                setbuf(stdin,NULL);
                if(action == 4)
                {
                        printf("Bye\n");
                        break;
                }
                if(action > 0 || action < max_action_index)
                {
                        printf("Enter your variables:");
                        scanf("%d %d",&left,&right);
                        result = actions[action](left,right);
                        printf("result is %d\n",result);
                }
                else
                {
                        printf("Bad action!\n");
                }
                // 清空输出缓冲
                while((action = getchar()) != '\n' && c != EOF);
                action = max_action_index;
                //setbuf(stdin,NULL);
        }
}