# include <stdio.h>
# include<malloc.h>
# define ND sizeof(struct List)
struct List
{int data;
 struct List *next;
};
void main()
{ int n,i=1,e,a;
  struct List *head;
  struct List *p,*q; 
   q=head=p=(struct List *)malloc(ND);
   printf("輸入鏈表的節(jié)點(diǎn)數(shù):");
   scanf("%d",&n);
   printf("輸入第1個(gè)結(jié)點(diǎn)的數(shù)據(jù):");
   scanf("%d",&p->data);
         i++;
       while(i<=n)
	 { q=(struct List *)malloc(ND);
	          p->next=q;
	   printf("輸入第%d個(gè)結(jié)點(diǎn)的數(shù)據(jù):",i);
       scanf("%d",&q->data);
	           p=q;
	           i++;                                                   
	 }                                          /*從鍵盤輸入鏈表數(shù)據(jù)*/ 
          q->next=NULL;
             q=p=head;
		            printf("所輸入的鏈表數(shù)據(jù):");
			        while(p!=NULL)
				   {   printf("%6d",p->data);
				          p=p->next;
				   }
					  printf("\n");
				      printf("輸入要?jiǎng)h除第幾個(gè)結(jié)點(diǎn):");
					   scanf("%d",&e);
                         p=head;
						 i=1;
					     if(e>n||e<1)
						 {  printf("ERROR!!!!!!!\n");
						      return;
						 }
						 else
						 {      if(e==1)
						 {       p=p->next;
						         free(head);
								 head=p;
						 }
						        else
								{   while(p->next&&i<e-1)
								{      p=p->next;
								        i++;
								}
								    q=p->next;
									p->next=q->next;
									free(q);
								    p=head;
								}
						 }                                       /*刪除鏈表中指定的結(jié)點(diǎn)*/
                         	printf("刪除后的鏈表數(shù)據(jù):");
			                    while(p!=NULL)
								{    printf("%6d",p->data);
				                             p=p->next;
								}
					            printf("\n輸入要在第幾個(gè)結(jié)點(diǎn)前插入:");
                                scanf("%d",&e);
                                printf("輸入所要插入的數(shù)據(jù):");
					            scanf("%d",&a);
					              p=head;
					                 i=1;
                                if(e>n||e<1)
								{ printf("ERROR!!!!!!!\n");
								    return;
								}
								
					            else
							   {  if(e==1)
							   {     q=(struct List *)malloc(ND);
						              q->data=a;
									  q->next=p;
									  head=p=q;
							   }
						          else 
								 { while(p->next&&i<e-1)
								   {        p=p->next;
						                       i++;
								   }
                                      q=(struct List *)malloc(ND);
						              q->data=a;
						              q->next=p->next;
                                      p->next=q;
									  p=head;
								 }
							   }                                    /*在指定結(jié)點(diǎn)前插入新結(jié)點(diǎn)*/
					  printf("插入結(jié)點(diǎn)后的鏈表:");
			              while(p!=NULL)
						  {     printf("%6d",p->data);
				                     p=p->next;
						  }
                                     printf("\n");
}