目录

• 链表的遍历
• 计算链表节点个数
• 查找结点
• 节点后插入新节点
• 节点前插入新节点
• • • • • 1.目标节点为头节点 （引起链表头变化）
        • 2.目标节点不是头节点
        • 节点前插入新节点（两种情况）完整版
• 删除节点
• • • • • • 课外知识：gcc ... -g
        • 1.删除头节点
        • 2.删的不是头节点
• 头插法动态创建链表
• 尾插法动态创建链表
• 更改节点（自己写的🤭）
• • • • • 不是头节点：
        • 改头节点

链表的遍历

struct test 
{int datastruct test *next;
}；void printlink(struct test *head)
{while(head!=NULL){printf("%d",head->data);head = head->next;     }}
int main()
{struct test t1 = {1,NULL};struct test t2 = {2,NULL};	struct test t3 = {3,NULL};t1.next = &t2;t2.next = &t3;printlink(&t1);return 0;
}

计算链表节点个数

int getlinknode(struct test *head)
{int cnt =0;while(head !=NULL){cnt++;head = head->next;     }return cnt;
}int main()
{int ret = getlinknode(&t1);printf("node = %d\n",ret);
}

查找结点

int searchnode(struct test *head,int data) //（链表头，要找的节点）
{while(head !=NULL){if(head->data == data){return 1;   }  head = head->next;     }return 0;
}int main(){
int t = searchnode(&t1,5);if(t==1){printf("有\n");     }else if(t ==0){printf("没有\n");     }}

节点后插入新节点

int insertFromBehind(struct test *head,int data,struct test *new)
{struct test *p = head;while(p != NULL){if(p->data == data){new->next = p->next;p->next = new;          return 1;    }      p = p->next;   }return 0;
}int main()
{struct test new = {5,NULL};insertFromBehind(&t1,3,&new);printlink(&t1);
}

 new->next = p->next;p->next = new; 

原理如图：

节点前插入新节点

分为两种情况：

1.目标节点为头节点 （引起链表头变化）

思想：这个函数返回值是个指针，把这个指针给链表头，去引起main函数里链表头变化

struct test *insertfromfor(struct test *head,int data,struct test *new)
{struct test *p = head;if(p->data == data){new->next = head;return new;         //把新的头返回给main        }
}int main()
{struct test *head = NULL;	struct test new2 = {7,NULL};head = &t1;  head = insertfromfor(head,1,&new2);    //让头等于新的头printf("after insert fromfor:\n");printlink(head);
}

2.目标节点不是头节点

添加进这部分就可以：struct test *insertfromfor(struct test *head,int data,struct test *new)while(p->next !=NULL){if(p->next->data == data){new->next = p->next;p->next = new;printf("insert ok\n");return head;   //在这里return head 不要忘也不要弄错位置}p = p->next;         }

节点前插入新节点（两种情况）完整版

struct test *insertfromfor(struct test *head,int data,struct test *new)
{struct test *p = head;if(p->data == data){new->next = head;return new;         }while(p->next !=NULL){if(p->next->data == data){new->next = p->next;p->next = new;printf("insert ok\n");return head;}p = p->next;         }
}int main()
{struct test new2 = {7,NULL};struct test new3 = {8,NULL};head = insertfromfor(head,1,&new2);printf("after insert fromfor:\n");printlink(head);head = insertfromfor(head,1,&new3);  //这里的1已经不是头了，在上一步操作后就变了printf("after insert fromfor not head:\n");printlink(head);
}

删除节点

课外知识：gcc … -g

              添加一个gdb调试的手段

删节点分两种情况

1.删除头节点

struct test *deletnode(struct test *head,int data)
{struct test *p = head;         if(p->data == data){head = head->next;free(p);return head;      }
}int main()
{head = deletnode(head,1);printlink(head);
}

2.删的不是头节点

struct test *deletnode(struct test *head,int data)
{struct test *p = head;while(p->next != NULL){              if(p->next->data == data){p->next = p->next->next ;          }return head;}
}int main()
{head = deletnode(head,2);printlink(head);
}

头插法动态创建链表

新来的是头，头一直在变，最后返回头

struct test *creathead(struct test *head)
{struct test *new ; int i;for(i=0;i<5;i++){new =(struct test *) malloc(sizeof(struct test));printf("输入内容：\n");scanf("%d",&(new->data));if(head==NULL){head = new;}else{new->next = head;head = new;              }}return head;
}int main()
{struct test *head = NULL;head = creathead(head);printlink(head);
}

优化：

struct test *insertfromhead(struct test *head,struct test *new)
{if(head==NULL){head = new;                          }else{new->next = head;head = new;              }    return head;
}struct test *creatlink(struct test *head)
{struct test *new;while(1){new =(struct test *)malloc(sizeof(struct test));printf("输入内容：\n");scanf("%d",&(new->data));if(new->data==0){printf("0 quit\n") ;return head;           }           head = insertfromhead(head,new);
}
}int main()
{struct test *head = NULL;	 head = creatlink(head);printlink(head);return 0;
}

尾插法动态创建链表

思想：遍历到最后一个节点，让最后一个节点的next= new

#include 
#include struct test
{int data;struct test *next;
};void printLink(struct Ltest* head)
{struct test* p = head;while(p != NULL){printf("%d ",p->data);p = p->next;}	putchar('\n');    
}struct test* insertfromtail(struct test *head,struct test *new)    //把creatlink中准备好的data连起来
{ struct test *p = head; if(p == NULL){head = new;return head;}while(p->next! =NULL){    p = p->next;}p->next = new;return head;
}struct test* createLink(struct test *head)    //  提示输入，获取内容，放到data里
{struct test *new = NULL;while(1){printf("input your new node data:\n");new = (struct test*)malloc(sizeof(struct test));scanf("%d",&(new->data));if(new->data == 0){printf("0 quit\n");free(new);            //如果第一次输入数据为0，则新节点new，malloc的空间没用，则free掉return head;}head = insertfromtail(head,new);       } 
}int main()
{struct test *head = NULL;head = createLink(head);printLink(head);	//打印链表return 0;
}

更改节点（自己写的🤭）

不是头节点：

改头节点