Reference

控制反转

实验1 C、Scheme、java实现回调

C函数指针

//op.c文件
typedef  int (*How_op)( int, int); //函数指针的种类
int op(int a, int b, How_op  how_op){ // call using function pointer
	return 2* how_op (a, b);    //2*运算暗示op函数体可以很复杂
}
 
//ood.h文件
//op.c用
typedef  int (*How_op)( int, int); //函数指针的种类
int op(int a, int b, How_op  how_op);

//上层模块，main.c文件
#include <stdio.h>
#include "ood.h"
int plus(int a,int b) {
	return a+b; 
}
 
void testCallback(void){
	int d =op(2, 5,  &plus);//
	printf("%d",d); //输出2*(2+5)
}
 
int main(void){	
	testCallback();
    return 0;
}

Scheme

;;;op.rkt
(define (op a b how-op)
   ( how-op a b) )
 
;;;上层模块，main.rkt
(load  "op.rkt")
;;;define function plus
(define (plus a b )
  (+ a b))
;;;Pass a Function as an Argument
(op 1 3 plus)
(op 2 3 (lambda(x y)(* x y)));;;Pass a lambda  as an Argument
 
(op  1+2i  3-4i *)
(op  (list 1 2 3) (list 4 5 6) append )

Java