链表的增删查改

main.c

#define _CRT_SECURE_NO_DEPRECATE
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include "func.h"

int main()
{
	pstu p;
	pstu phead = NULL, ptail = NULL;	//代表链表
	int i;
	float f;
	while (scanf("%d", &i) != EOF)	//链表的头插，尾插，有序插入
	{
		list_tail_insert(&phead, &ptail, i);
		//list_head_insert(&phead, &ptail, i);
		//list_sort_insert(&phead, &ptail, i);
	}
	list_print(phead);
	/*while (printf("please input delete num:"),scanf("%d",&i)!=EOF)	//链表删除
	{
		list_delete(&phead, &ptail, i);
		list_print(phead);
	}
	while (printf("please input modify num:"), scanf("%d", &i) != EOF)	//链表修改
	{
		list_modify(&phead, i,f);
		list_print_score(phead);
	}*/
	system("pause");
}

func.h

#include<stdio.h>
#include<stdio.h>
#include<string.h>
typedef struct student
{
	int num;
	float score;
	struct student* pNext;
}stu,*pstu;

//尾插法
void list_tail_insert(pstu*,pstu*, int);
//头插法
void list_head_insert(pstu*, pstu*, int);
//有序插入法
void list_sort_insert(pstu*, pstu*, int);
//删除法
void list_delete(pstu*, pstu*, int);
//链表修改
void list_modify(pstu, int,float);
//链表打印
void list_print(pstu);
void list_print_score(pstu);

func.c

#define _CRT_SECURE_NO_DEPRECATE
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include "func.h"


void list_tail_insert(pstu* pphead, pstu* pptail, int i) {
	pstu pnew;
	pnew = (pstu)malloc(sizeof(stu));
	memset(pnew, 0, sizeof(stu));
	pnew->num = i;
	if (NULL == *pptail)		//判断链表是否为空，为空时，pnew既为头又为尾
	{
		*pphead = pnew;
		*pptail = pnew;
	}
	else
	{
		(*pptail)->pNext = pnew;	//将新结点的地址赋值为尾结点的pnext
		*pptail = pnew;		//新结点变为链表尾部
	}
}

//只打印学号
void list_print(pstu phead)
{
	while (phead != NULL)
	{
		printf("%3d", phead->num);
		phead = phead->pNext;
	}
}
//打印学号和分数
void list_print_score(pstu phead)
{
	while (phead != NULL)
	{
		printf("%3d %5.2f", phead->num, phead->score);
		phead = phead->pNext;
	}
	printf("\n");
}

void list_head_insert(pstu* pphead, pstu* pptail, int i)
{
	pstu pnew;
	pnew = (pstu)malloc(sizeof(stu));
	memset(pnew, 0, sizeof(stu));
	pnew->num = i;
	if (NULL == *pphead)		//如果链表为空，pnew赋给phead,ptail
	{
		*pphead = pnew;
		*pptail = pnew;
	}
	else
	{
		pnew->pNext = *pphead;		//原有链表的头指针赋值给新结点的pNext
		*pphead = pnew;					//新结点变为链表头
	}
}

void list_sort_insert(pstu* pphead, pstu* pptail, int i)
{
	pstu pcur;
	pstu ppre;
	pstu pnew;
	pnew = (pstu)malloc(sizeof(stu));
	memset(pnew, 0, sizeof(stu));
	pnew->num = i;
	pcur = *pphead;			//让两个指针都指向链表头
	ppre = *pphead;
	if (NULL == pcur)		//判断两个链表是否为空
	{
		*pphead = pnew;
		*pptail = pnew;
	}
	else if(i<pcur->num)		//判断i是否小于头部数据，若是则将其插入头部
	{
		pnew->pNext = pcur;		//原有链表的头指针赋给新节点的pNext
		*pphead = pnew;			//新结点变为链表头
	}
	else
	{
		while (pcur=!NULL)		//插入中间
		{
			if (pcur->num>i)
			{
				ppre->pNext = pnew;
				pnew->pNext = pcur;
				break;
			}
			ppre = pcur;		//前指针赋给后指针
			pcur = pcur->pNext;
		}
		if (NULL==pcur)
		{
			(*pptail)->pNext = pnew;		//将新结点的地址赋给尾结点的pNext
			*pptail = pnew;						//新结点变为链表尾部
		}
	}
}
void list_delete(pstu* pphead, pstu* pptail, int delete_num)
{
	pstu pcur, ppre;
	pcur = *pphead;
	ppre = pcur;
	if (pcur!=NULL)
	{
		if (pcur->num=delete_num)		//如果要删除的num和头结点的值相等
		{
			*pphead = pcur->pNext;		//改变头指针，指向下一个结点
			if (NULL==*pphead)				//删除后链表为空
				{
				*pptail = NULL;
			}
			free(pcur);								//释放空间					
		}
		else
		{
			//删除中间结点及尾结点
			while (pcur!=NULL)
			{
				if (pcur->num==delete_num)
				{
					ppre->pNext = pcur->pNext;
					free(pcur);
					break;
				}
				ppre = pcur;
				pcur = pcur->pNext;
			}
			if (NULL==ppre->pNext)
			{
				*pptail = ppre;
			}
			if (NULL==ppre->pNext)
			{
				*pptail = ppre;
			}
			if (NULL==pcur)
			{
				printf("no this node\n");
			}
		}
	}
	else
	{
		printf("list is NULL\n");
	}
}

void list_modify(pstu phead, int i, float f)
{
	while (phead!=NULL)
	{
		if (phead->num==i)
		{
			phead->score = f;
			break;
		}
		phead = phead->pNext;
	}
	if (NULL==phead)
	{
		printf("no this node\n");
	}
}