判斷鏈表是否爲空而且求鏈表長度

#include<stdio.h>

#include<stdlib.h>

#include<malloc.h>

struct node

{

int data;

struct node *pnext;

};

struct node *creat_list();

void traverse_list(struct node *phead);

bool is_empty(struct node *phead);

int lenght_list(struct node *phead);

int main()

{

struct node *phead;

phead=creat_list();

traverse_list(phead);

if(is_empty(phead))

printf("鏈表不爲空！\n");

else

printf("鏈表爲空！\n");

int len=lenght_list(phead);

printf("鏈表的節點個數爲：%d\n",len);

return 0;

}

//建立鏈表函數

struct node *creat_list()

{

struct node *phead,*ptail,*pnew;

phead=(struct node *)malloc(sizeof(struct node));

ptail=phead;

ptail->pnext=NULL;

if(NULL==phead)

{

printf("分配內存失敗,終止程序！\n");

exit(0);

}

int len;//表示要建立的節點數

int val;

printf("請輸入要建立的節點數：");

scanf("%d",&len); 

for(int i=0;i<len;i++)

{

printf("請輸入%d個節點的數據：",i+1);

scanf("%d",&val);

pnew=(struct node *)malloc(sizeof(struct node));

if(NULL==pnew)

{

printf("分配內存失敗,終止程序！\n");

exit(0);

}

pnew->data=val;

ptail->pnext=pnew;

pnew->pnext=NULL;

ptail=pnew;

} 

return phead;

}

//遍歷鏈表函數

void traverse_list(struct node *phead)

{

struct node *p=phead->pnext;

while(p!=NULL)

{

printf("%d ",p->data);

p=p->pnext;

} 

printf("\n");

return ;

} 

//判斷鏈表是否爲空函數 

bool is_empty(struct node *phead)

{

if(phead->pnext!=NULL)

return true;

else

return false;

}

int lenght_list(struct node *phead)

{

struct node *p=phead->pnext;

int len=0;

while(p!=NULL)

{

len++;

p=p->pnext;

}

return len;

}