malloc一个动态链表

描述：按图实现一个人员管理功能（录入，增加，删除）

代码实现：

1. 变量声明 和 main函数：

#include 
#include 
#include 

int listCount = 0; 
typedef struct _Student
{
    char name[20];
    int  number;

    struct _Student *pNext;
}STUDENT;

void Print_Student_Info(STUDENT *pList)
{
    STUDENT *pNewNode = NULL;

    unsigned int index = 0;

    if (NULL == pList ||
        NULL == pList->pNext)
    {
        printf("n---- student info is not exist ----nn");
        return ;
    }

    printf("n---- the list has %d members ----nn", listCount);
    
    index = 1;
    pNewNode = pList->pNext;
    while (NULL != pNewNode)
    {
        printf("the NO%02d member is:n", index);
        printf("    the name is %sn", pNewNode->name);
        printf("    the number is %dnn", pNewNode->number);

        index++;
        pNewNode = pNewNode->pNext;
    }
    
    return ;
}

int main(int argc, char *argv[])
{
    STUDENT *pStudentlist = NULL;

    
    pStudentlist = Create_Student_Info();
    Print_Student_Info(pStudentlist);
    if (NULL == pStudentlist)
    {
        return 0;
    }

    
    Insert_Head_Student_Info(pStudentlist);
    Print_Student_Info(pStudentlist);

    
    Insert_End_Student_Info(pStudentlist);
    Print_Student_Info(pStudentlist);

    
    Delete_Student_Info(pStudentlist);
    Print_Student_Info(pStudentlist);
    return 0;
}

2. 录入数据功能：

实现：（退出时会创建一个结点，需要free，否则会造成内存泄漏）

STUDENT *Create_Student_Info()
{
    STUDENT *pHeadNode = NULL;
    STUDENT *pEndNode  = NULL;
    STUDENT *pNewNode  = NULL; 

    
    printf("please enter [Name Number]:n");
    pNewNode = (STUDENT *)malloc(sizeof(STUDENT));
    if (NULL == pNewNode)
    {
        printf("init head node failed!n");
        return NULL;
    }
    memset(pNewNode, 0, sizeof(STUDENT));

    listCount = 0;
    pHeadNode = pNewNode;
    pEndNode  = pNewNode;

    do{
        
        pNewNode = (STUDENT *)malloc(sizeof(STUDENT));
        if (NULL == pNewNode)
        {
            printf("create %d-th node failed!n", (listCount+1));
            return pHeadNode;
        }
        scanf("%s", &pNewNode->name[0]);
        scanf("%d", &pNewNode->number);
        pNewNode->pNext = NULL;

        if (0 != pNewNode->number)
        {
            listCount++;
            pEndNode->pNext = pNewNode;
            pEndNode        = pNewNode;
        }

    }while (0 != pNewNode->number);
    
    
    free((void*)pNewNode);

    return pHeadNode;
}

3. 插入数据功能

3.1 头插：

实现：

void Insert_Head_Student_Info(STUDENT *pList)
{
    STUDENT *pNewNode = NULL;

    if (NULL == pList)
    {
        printf("n---- student is not exist, insert head failed! ----nn");
        return ;
    }

    printf("insert member at head:n");
    pNewNode = (STUDENT *)malloc(sizeof(STUDENT));
    if (NULL == pNewNode)
    {
        printf("ncreate insert node at head failed!n");
        return ;
    }
    scanf("%s", &pNewNode->name[0]);
    scanf("%d", &pNewNode->number);
    pNewNode->pNext = NULL;

    
    listCount++;
    pNewNode->pNext = pList->pNext;
    pList->pNext    = pNewNode;

    return ;
}

3.2 尾插：

 实现：

void Insert_End_Student_Info(STUDENT *pList)
{
    STUDENT *pEndNode = NULL;
    STUDENT *pNewNode = NULL;

    if (NULL == pList)
    {
        printf("ninsert member node at end failed!n");
        return ;
    }

    pEndNode = pList;
    while(NULL != pEndNode->pNext)
    {
        pEndNode = pEndNode->pNext;
    }

    printf("insert member at end:n");
    pNewNode = (STUDENT *)malloc(sizeof(STUDENT));
    if (NULL == pNewNode)
    {
        printf("ncreate insert node at end failed!n");
        return ;
    }
    scanf("%s", &pNewNode->name[0]);
    scanf("%d", &pNewNode->number);
    pNewNode->pNext = NULL;
    
    
    listCount++;
    pEndNode->pNext = pNewNode;

    return ;
}

4. 删除数据功能：

实现：

void Delete_Student_Info(STUDENT *pList)
{
    STUDENT *pPerNode = NULL;
    STUDENT *pCurNode = NULL;

    char deleteName[20];

    if (NULL == pList ||
        NULL == pList->pNext)
    {
        printf("n---- student info is not exist ----nn");
        return ;
    }

    printf("delete, please input student name:");
    scanf("%s", &deleteName[0]);

    pPerNode = pList;
    pCurNode = pList->pNext;
    while (NULL != pCurNode)
    {
        if (0 == strcmp(pCurNode->name, deleteName))
        {
            break;
        }

        pPerNode = pCurNode;
        pCurNode = pCurNode->pNext;
    }
    
    if (NULL != pCurNode)
    {
        printf("%s student delete successn", deleteName);
        pPerNode->pNext = pCurNode->pNext;
        free(pCurNode);
        listCount--;
    }
    else
    {
        printf("%s student not exist!n", deleteName);
    }

    return ;
}