C语言学习记录4 — 链表3

链表3 — 单链表结点删除

局部代码详解

目的：实现单链表数据为x的结点删除

//删除结点函数
void del(List *head,int x){
    if (head == NULL) {
        return;
    }
     //单独判断头结点，如果为x则删除
    if (head->d == x) {
        List *temp = head;
        head = head->next;
        free(temp);    //删除结点（释放内存）
    }
    //定义结构体指针
    List *p = head;

    //头节点判断结束，顺序判断各结点是否需要删除
    while (p->next != NULL) {
        if (p->next->d == x) {
            List *temp = p->next;    //将需要删除的结点储存在结构体指针temp中
            p->next = p->next->next;   //将指针移动到下一结点处
            free(temp);    //删除结点（释放内存）
        }else {
            p = p->next;    //不需要删除时，判断下一结点是否删除
        }
    }
    return;
}

完整代码实现

#include <stdio.h>
#include <stdlib.h>

//定义结点
typedef struct LinkList{
    int d;
    struct LinkList *next;
} List;

//尾插法
List *add_list(List *head, int data){
    List *newnode = (List *)malloc(sizeof(List));

    newnode->d = data;
    newnode->next = NULL;

    if (head ==NULL) {
        head = newnode;
    }else {
        List *pT = head;
        while (pT->next != NULL) {
            pT = pT->next;
        }
        pT->next = newnode;
    }
    return head;
}

//输出函数
void output(List *head){
    List *pT = head;
    while (pT != NULL) {
        printf("%d",pT->d);
        printf(" ");
        pT = pT->next;
    }
}

//删除结点函数
void del(List *head,int x){
    if (head == NULL) {
        return;
    }

    if (head->d == x) {
        List *temp = head;
        head = head->next;
        free(temp);
    }
   
    List *p = head;
    while (p->next != NULL) {
        if (p->next->d == x) {
            List *temp = p->next;
            p->next = p->next->next;
            free(temp);
        }else {
            p = p->next;
        }
    }
    return;
}

int main() {
    int n,i,x;
    List *head = NULL;
    scanf("%d",&n);
    getchar();
    scanf("%d",&x);
    int a[n];

    for (i=0; i < n; i++) {
        scanf("%d",&a[i]);
        getchar();
    }
    for (i=0; i < n; i++) {
        head = add_list(head, a[i]);
    }
    del(head,x);   //调用删除结点函数
    output(head);
    return 0;
}