指针函数与函数指针

Posted 2022-03-25 helloworld2019

指针函数：->int*p();

函数指针：->int (*p)();

定义char 类型的指针，返回字符串：

指针函数：使用指针作为返回值的函数

//指针函数
#include<iostream>
char *getchar(char);
char *getchar(char c)
	switch(c)
		case ‘A‘:return "apple";
		case ‘B‘ :return "banana";
		case ‘C‘: return "Cat";
		case ‘D‘: return "Dog";
		default: return "Nome";
	

int main()
	 char input;
	 printf("请输入一个字母");
	 scanf("%c",&input);
	printf("%s\\n",getchar(input)) ;
	 return 0;
 

函数指针;

//指针函数
#include<iostream>
int square(int num)
	return num*num;


int main()
	int num;
	int (*fp)(int);
	printf("请输入一个整数：");
	scanf("%d",&num);
	fp=square;
	printf("%d*%d=%d ",num,num,(*fp)(num));
printf("%d*%d=%d ",num,num,fp(num));//fp相当于函数名

return 0;
 

函数指针作为参数:

//函数指针作为参数:
#include<iostream>
int add(int num1,int num2)
	return num1+num2;

int sub(int num1,int num2)
	return num1-num2;

int calc(int (*fp)(int,int),int num1,int num2)
	return (*fp)(num1,num2);

int main()
	printf("3+5=%d\\n",calc(add,3,5));
	printf("3-5=%d\\n",calc(sub,3,5));	
	
return 0;
 

将函数指针作为返回值

#include <stdio.h>

int add(int, int);
int sub(int, int);
int calc(int (*)(int, int), int, int);
int (*select(char))(int, int);

int add(int num1, int num2)

	return num1 + num2;


int sub(int num1, int num2)

	return num1 - num2;


int calc(int (*fp)(int, int), int num1, int num2)

	return (*fp)(num1, num2);


int (*select(char op))(int, int)

	switch(op)
	
		case ‘+‘: return add;
		case ‘-‘: return sub;
	


int main()

	int num1, num2;
	char op;	
	int (*fp)(int, int);
printf("输入一个式子(3-2)");
	scanf("%d%c%d", &num1, &op, &num2);

	fp = select(op);
	printf("%d %c %d = %d\\n", num1, op, num2, calc(fp, num1, num2));

	return 0;