函數返回函數指針

C代碼 
#include <stdio.h> 
 
char *ops[3] = { "sum", "sub", "mul" }; 
 
int sum(int a, int b) 
{ 
        return a + b; 
} 
 
int sub(int a, int b) 
{ 
        return a - b; 
} 
 
int mul(int a, int b) 
{ 
        return a * b; 
} 
 
void show(int opnum) 
{ 
        printf("Do the operation:%s\n", ops[opnum]); 
} 
 
int (*operation(int opnum, void (*fun) (int))) (int, int) 
{ 
        fun(opnum); 
        switch (opnum) { 
        case 0: 
                return sum; 
                break; 
        case 1: 
                return sub; 
                break; 
        case 2: 
                return mul; 
                break; 
        default: 
                break; 
        } 
 
} 
 
int main(int argc, char *argv[]) 
{ 
        int a = 33; 
        int b = 17; 
        printf("Here a=%d, b=%d\n", a, b); 
        printf("\tThe result is :%d\n", operation(0, show) (a, b)); 
        printf("\tThe result is :%d\n", operation(1, show) (a, b)); 
        printf("\tThe result is :%d\n", operation(2, show) (a, b)); 
         
        return 0; 
}