本文总结了几个递归算法的应用场景。

先来热身：计算从1+2+….+100的值

#include<stdio.h>

int sum(int val)
{
    if(val == 100)
        return 100;

    return val + sum(val+1);
}

int main(void)
{
    sum(1);
    return 0;
}

1.经典问题，斐波切纳数列解法

/***
题目：输出斐波那契数列的对应项的值。斐波那契数列：0,1,1,2,3,5,8,13.... 要求函数实现计算，如：fibo(0)输出0 ，fibo(4)则输出5  
***/

#include<stdio.h>


int fibo(int m)
{
	if(m < 2){
		return m;
	}
	return fibo(m - 1) + fibo(m - 2);
}


int main(int argc,char * argv[])
{
	int input;

	while(1){
		input = 0;

		printf("Pls input a fibo number:");

		scanf("%d",&input);

		if(input < 0){
			printf("you had input an invalid value,pls input a number no less than 0\n");

			continue;
		}
		printf("The result is: %d\n",fibo(input));
	}
	return 0;
}

2. 实现单向链表翻转

typedef struct LinkListNode{
	int num;
	struct LinkListNode * pNext;
}T_Node;


T_Node * ReverseLinkList(T_Node * pHead)
{
	T_Node *pCurHead, *pNext;

	if(pHead == NULL)
		return NULL;

	if(pHead->pNext == NULL)
		return pHead;
	
	pCurHead = pHead;
	pNext = pHead->pNext;

	pHead = ReverseLinkList(pNext);
	pNext->pNext = pCurHead;
	pCurHead->pNext = NULL;
	
	return pHead;
}