查找单链表中的某几个相同的数，并把它们组成新的链表，原链表不变

方法一（有返回值）： #include <stdio.h> #include <stdlib.h> typedef struct person { int age; struct person *next; }per; per *tail_list(per *one, int num) { per *temp = (per *)malloc(sizeof(per)); temp->age = num; if(NULL == one) { return temp; } per *head = one; while(one->next) { one = one->next; } one->next = temp; return head; } void show(per *head) { if(NULL == head) { return; } while(head) { printf("age is %d\n",head->age); head = head->next; } } per *get_put(per *head, int n) { per *new_list = NULL; per *curr = head; //声明两个指针指向原链表的头 per *past = head; if(NULL == head) { return NULL; } while(past->next) { if(n == past->age) //如果要找的数在第一个 { curr = past; head = head->next; past = head; curr->next = new_list; //组成新的链表 new_list = curr; } else if(n == past->next->age) //如果要找的数在最后一个 { curr = past->next; past->next = curr->next; //取出最后一个数 curr->next = new_list; new_list = curr; } else { past = past->next; //取下一个 } } return new_list; } int main() { per *head = NULL; head = tail_list(head,12); head = tail_list(head,12); head = tail_list(head,10); head = tail_list(head,12); head = tail_list(head,10); head = tail_list(head,12); head = tail_list(head,12); printf("============old list==================\n"); show(head); printf("=========after find new_list==========\n"); per *new_list = get_put(head,12); show(new_list); return 0; }

方法二（无返回值）：

（1）无头头插单链表：

#include <stdio.h> #include <stdlib.h> typedef struct person { int age; struct person *next; }per; void head_list(per **one, int num) { per *temp = (per *)malloc(sizeof(per)); temp->age = num; temp->next = (*one); (*one) = temp; } void show(per *head) { if(NULL == head) { return; } while(head) { printf("age is %d\n",head->age); head = head->next; } } per *get_put(per *head,int n) { per *new_list = NULL; if(NULL == head) { return NULL; } while(head) { if(n == head->age) { head_list(&new_list,n); } head = head->next; } return new_list; } int main() { per *head = NULL; head_list(&head,10); head_list(&head,12); head_list(&head,10); head_list(&head,12); head_list(&head,10); head_list(&head,12); show(head); printf("========get new_list========\n"); per *new = get_put(head,12); show(new); return 0; } （2）无头尾插单链表：

#include <stdio.h> #include <stdlib.h> typedef struct person { int age; struct person *next; }per; void *tail_list(per **one, int num) { per *temp = (per *)malloc(sizeof(per)); temp->age = num; temp->next = NULL; while(*one) { one = &((*one)->next); } (*one)= temp; } void show(per *head) { if(NULL == head) { return; } while(head) { printf("age is %d\n",head->age); head = head->next; } } per *get_put(per *head, int n) { per *new_list = NULL; while(head) { if(n == head->age) { tail_list(&new_list,n); } head = head->next; } return new_list; } int main() { per *head = NULL; tail_list(&head,10); tail_list(&head,12); tail_list(&head,10); tail_list(&head,12); tail_list(&head,10); tail_list(&head,12); show(head); puts("=======after new_list==========="); per *new = get_put(head,12); show(new); return 0; }