2024-2-4-复习作业

源代码：

#include <stdio.h>
#include <stdlib.h>
typedef int datatype; 
typedef struct Node
{datatype data;struct Node *next;struct Node *prev;
}*DoubleLinkList;DoubleLinkList create()
{DoubleLinkList s=(DoubleLinkList)malloc(sizeof(struct Node));s->data=0;s->next=s->prev=NULL;return s;
}
DoubleLinkList head_insert(DoubleLinkList head ,int element)
{DoubleLinkList s=create();s->data=element;if(head==NULL) head=s;else{s->next=head;head->prev=s;head=s;}return head;
}DoubleLinkList rear_insert(DoubleLinkList head,int element)
{DoubleLinkList s=create();s->data=element;if(head==NULL)  head=s;else{DoubleLinkList p=head;while(p->next!=NULL){p=p->next;}p->next=s;s->prev=p;}return head;
}
DoubleLinkList head_delete(DoubleLinkList head)
{if(head==NULL) return NULL;DoubleLinkList del=head;head=head->next;head->prev=NULL;free(del);del=NULL;return head;}DoubleLinkList rear_delete(DoubleLinkList head)
{if(head==NULL) return NULL;if(head->next==NULL){free(head);head=NULL;return head;}    DoubleLinkList p=head;while(p->next){p=p->next;}p->prev->next=NULL;free(p);p=NULL;return head;    
}void output(DoubleLinkList head)
{if(head==NULL) { printf("empty\n"); return;}DoubleLinkList p=head;while (p->next!=NULL){printf("%d ",p->data);p=p->next;}printf("%d \n",p->data);
}
int length(DoubleLinkList head)
{int len=0;if(head==NULL) return len;while(head!=NULL){head=head->next;len++;}return len;
}
void insert_pos(DoubleLinkList head,int pos,int element)
{int len=length(head);//printf("len=%d\n",len);if( len==0 || pos<=0 || pos>len ) {puts("error pos !"); return;}DoubleLinkList p=head;for(int i=1;i<pos;i++){p=p->next;}DoubleLinkList s=create();s->data=element;datatype t=p->data;p->data=s->data;s->data=t;if(p->next==NULL) {p=p->prev;}s->next=p->next;s->prev=p;p->next->prev=s;p->next=s;
}DoubleLinkList delete_pos(DoubleLinkList head,int pos)
{int len=length(head);if( len==0 || pos<=0 || pos>len ) {puts("error pos !"); return NULL;}if(pos==1){head=head_delete(head);return head;}DoubleLinkList p=head;for(int i=1;i<pos;i++){p=p->next;}if(pos==len){head=rear_delete(head);return head;}DoubleLinkList del=p;p->prev->next=p->next;p->next->prev=p->prev;free(del);del=NULL;return head;}
void update_pos(DoubleLinkList head,int pos,int element)
{if(pos>length(head) || pos<=0 || head==NULL){puts("error pos !");return ;   }DoubleLinkList p=head;for(int i=1;i<pos;i++){p=p->next;}p->data=element;   }void search_pos(DoubleLinkList head,int pos)
{if(pos>length(head) || pos<=0 || head==NULL){puts("error pos !");return ;   }DoubleLinkList p=head;for(int i=1;i<pos;i++){p=p->next;}printf("The search element is %d \n",p->data);
}int main(void) 
{int n,element,pos;DoubleLinkList head=NULL;printf("please enter n : " );scanf("%d",&n);for(int i=0;i<n;i++){printf("please enter %d element : ",i+1 );scanf("%d",&element);//head=head_insert(head,element);head=rear_insert(head,element);}head=head_delete(head);head=rear_delete(head);output(head);printf("please enter insert pos : ");scanf("%d",&pos);printf("please enter insert element : ");scanf("%d",&element);insert_pos(head,pos,element);printf("please enter delete pos : ");scanf("%d",&pos);head=delete_pos(head,pos);printf("please enter update pos : ");scanf("%d",&pos);printf("please enter update element : ");scanf("%d",&element);update_pos(head,pos,element);printf("please enter search pos : ");scanf("%d",&pos);search_pos(head,pos);output(head);return 0;
}

1>

要求：

效果图：

2>

要求：

效果图：

3>

要求：

答：

（1）栈中定义的变量符合先进后出，队列则符合先进先出

（2）栈中只能从对栈顶操作，队列可以对队头、队尾操作

4>

要求：

答：

在堆区动态申请内存后，释放内存时未将释放指针指向堆区首地址，导致内存无法回收成功。