C语言程序设计第四版（何钦铭、颜晖）第十一章指针进阶之奇数值结点链表

7. 奇数值结点链表:输入若干个正整数(输入-1为结束标志)建立一个单向链表,头指针为L,将链表L中奇数值的结点重新组成一个新的链表NEW,并输出新建链表的信息。试编写相应程序。

第一种方案：

#include<stdio.h> #include<stdlib.h> struct num_node { int x; struct num_node *next; }; int main() { int a; struct num_node *L = NULL, *NEW = NULL, *p = NULL, *s = NULL, *q = NULL; // 输入链表 scanf("%d", &a); while(a != -1) { p = (struct num_node*)malloc(sizeof(struct num_node)); p->x = a; p->next = NULL; if(L == NULL) { L = p; s = L; } else { s->next = p; s = p; } scanf("%d", &a); } // 从原链表中提取奇数节点，组成新链表 p = L; q = NULL; // q 用于追踪新链表的尾节点 while(p != NULL) { if(p->x % 2 != 0) { // 如果是奇数 s = (struct num_node*)malloc(sizeof(struct num_node)); s->x = p->x; s->next = NULL; if(NEW == NULL) { NEW = s; q = NEW; } else { q->next = s; q = s; } } p = p->next; // 关键：移动原链表指针 } // 输出新链表（只含奇数） q = NEW; while(q != NULL) { printf("%d ", q->x); q = q->next; } printf("\n"); // 释放内存（可选，但好习惯） // 释放原链表 p = L; while(p != NULL) { struct num_node* temp = p; p = p->next; free(temp); } // 释放新链表 q = NEW; while(q != NULL) { struct num_node* temp = q; q = q->next; free(temp); } return 0; }

输入样例：1 2 3 4 5 6 7 8 9 -1

输出结果：1 3 5 7 9

第二种方案：

#include<stdio.h> #include<stdlib.h> struct num_node{ int x; struct num_node *next; }; struct num_node *createList(struct num_node *head); struct num_node *Insert_node(struct num_node *head,struct num_node *p); struct num_node *Select_node(struct num_node *head); void print(struct num_node *head); void free_node(struct num_node *head); int main() { struct num_node *L=createList(NULL),*NEW=Select_node(L); print(NEW); free_node(L); free_node(NEW); return 0; } //创建链表 struct num_node *createList(struct num_node *head){ int a; struct num_node *p=NULL; scanf("%d",&a); while(a!=-1){ p=(struct num_node*)malloc(sizeof(struct num_node)); p->x=a; p->next=NULL; head=Insert_node(head,p); scanf("%d",&a); } return head; } //插入结点 struct num_node *Insert_node(struct num_node *head,struct num_node *p){ struct num_node *s=head; if(head==NULL){ head=p; s=head; } else{ while(s->next!=NULL){ s=s->next; } s->next=p; s=p; } return head; } //摘取奇数结点形成新的链表 struct num_node *Select_node(struct num_node *head){ struct num_node *NEW=NULL,*p=head,*s=NULL,*q=NULL; while(p!=NULL){ if(p->x%2!=0){ s=(struct num_node *)malloc(sizeof(struct num_node)); s->x=p->x; s->next=NULL; if(NEW==NULL){ NEW=s; q=NEW; } else{ q->next=s; q=s; } } p=p->next; } return NEW; } //打印链表 void print(struct num_node *head){ struct num_node *q=head; while(q!=NULL){ printf("%d ",q->x); q=q->next; } } //释放结点 void free_node(struct num_node *head){ struct num_node *q=head,*temp=NULL; while(q!=NULL){ temp=q; q=q->next; free(temp); } }

输入样例：1 2 3 4 5 6 7 8 9 11 13 -1

输出结果：1 3 5 7 9 11 13