c 언어 데이터 구조 분석 2 의 링크 삽입 삭제

#include <stdlib.h>

#include <stdio.h>

struct test{

	int value;

	struct test *next;

};

struct test* create(){ //  create   ，   struct test*              

	test *head,*tail,*p;

	head=tail=NULL;

	//head        ，p     ，tail        ，      

	int i;



	for(int j=0;j<4;j++)

	{

		scanf("%d",&i);

		//(    )malloc(sizeof(    ))       ，      free()   

		p=(struct test*)malloc(sizeof(struct test)); //         

		p->value=i;

		p->next=NULL;



		if(head==NULL)

		{

			head=tail=p;		//      

		}

		else{

			tail=tail->next;	//   set tail->next                  			

		}

		tail->next=p;			//         ；

	}



	return head;

};



struct test* insert(struct test* ar,int a,int b)	//      

{

	// a       ，b        ar       

	struct test *p,*q,*s;

	s=(struct test*)malloc(sizeof(struct test));

	s->value=b;



	if(ar==NULL)	//        

	{

		ar=s;

		s->next=NULL;

	}

	

	if(ar->value==a)//            ，      

	{

		s->next=ar;

		ar=s;

	}else{			//      

		p=ar;

		while(p->value!=a && p->next!=NULL)	//    a    ，while    

		{

			q=p;	//          p

			p=p->next;

		}

		if(p->value==a)	//      	

		{

			q->next=s;  //p         p       p         q

			s->next=p;

			

		}else		//        

		{

			p->next=s;

			s->next=NULL;

		}

	}



	

	return ar;

}

struct test* del(struct test* ar,int n)　　//      

{

	struct test *q,*p;

	if(ar==NULL)

		printf("the table is null
");

	else if(ar->value==n)

	{

		ar=ar->next;

	}else

	{

		p=ar;

		while(p->next!=NULL && p->value!=n)

		{

			q=p;

			p=p->next;

		}

		if(p->value!=n)

			printf("no the num
");

		else

		{

			q->next=p->next;

			free(p);

		}

	}



	return ar;

}



void showDate(struct test* p)　　//      

{

	while (p)

	{		

		printf("%d
",p->value);

		p=p->next;

	}

}

int main(int argc, char* argv[])

{



	struct test *p,*head;

	int a,b,d;

	head=NULL;

	p=create();

	head=p;

	showDate(p);	



	printf("num
");	//    

	scanf("%d",&a);

	printf("insert num
");

	scanf("%d",&b);



	p=insert(head,a,b);

	head=p;//          

	printf("new p
");

	showDate(p);



	printf("del num
");	//    

	scanf("%d",&d);

	p=del(head,d);

	showDate(p);



	return 0;

}