在链表前后插入结点

在链表后加入节点。

#include<stdio.h>
struct Test
{
	int data;
	struct Test *next;
	
};

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;
}
void printLink(struct Test* head)
{
	struct Test* point=head;
	while(point!=NULL){
		printf("%d ",point->data);
		point=point->next;
		
	}	
}

int getNum(struct Test* head)
{
	int num=0;
	struct Test *p=head;
	while(p!=NULL){
		num++;
		p=p->next;
	}
	return num;
	
}

int searchNum(struct Test* point,int data)
{
	
	while(point!=NULL){
		if(point->data==data){
			return 1;
		}
		point=point->next;
	}
	return 0;
	
}

int main()
{

	
	struct Test t1={1,NULL};
	struct Test t2={2,NULL};
	struct Test t3={3,NULL};
	struct Test t4={4,NULL};
	struct Test t5={5,NULL};
	
	t1.next=&t2;
	t2.next=&t3;
	t3.next=&t4;
	t4.next=&t5;
	
	struct Test new={100,NULL};
	printf("use t1 to print three nums!\n");
	printLink(&t1);
	putchar('\n');
	puts("after insert behind:");
	insertFromBehind(&t1,3,&new);
	printLink(&t1);
	/*putchar('\n');
	int ret=getNum(&t1);
	printf("链表里的个数是：%d\n",ret);
	
	ret = searchNum(&t1,1);
	if(ret==0){
		printf("no 1\n");
	}
	else{
		printf("have 1\n");
	}
	ret = searchNum(&t1,8);
	if(ret==0){
		printf("no 8\n");
	}
	else{
		printf("have 8\n");
	}*/
	return 0;
}

建立一个头结点指针然后判断他是否为空，不为空时将在这个数据前后链接起来。注意这边new需要定义。

在链表后前加入一个数据

#include<stdio.h>
struct Test
{
	int data;
	struct Test *next;
	
};

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("search ok!\n");
			return head;
		}
		p=p->next;
	}
	 printf("do not have %d\n",data);
	 return head;
}

void 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;
			
		}
		p=p->next;
	}
		
}
void printLink(struct Test* head)
{
	struct Test* point=head;
	while(point!=NULL){
		printf("%d ",point->data);
		point=point->next;
		
	}	
}

int getNum(struct Test* head)
{
	int num=0;
	struct Test *p=head;
	while(p!=NULL){
		num++;
		p=p->next;
	}
	return num;
	
}

int searchNum(struct Test* point,int data)
{
	
	while(point!=NULL){
		if(point->data==data){
			return 1;
		}
		point=point->next;
	}
	return 0;
	
}

int main()
{

	
	struct Test t1={1,NULL};
	struct Test t2={2,NULL};
	struct Test t3={3,NULL};
	struct Test t4={4,NULL};
	struct Test t5={5,NULL};
	
	struct Test *head=NULL;
	
	t1.next=&t2;
	t2.next=&t3;
	t3.next=&t4;
	t4.next=&t5;
	
	head=&t1;
	struct Test new={100,NULL};
	
	printf("use t1 to print three nums!\n");
	printLink(head);
	
	putchar('\n');
	puts("after insert behind:");
	insertFromBehind(head,5,&new);
	printLink(head);
	
	struct Test new2={101,NULL};
	putchar('\n');
	head = insertFromFor(head,2,&new2);
	puts("after insert forward:");
	printLink(head);

	return 0;
}

同理