輸入若干個正整數(輸入-1為結束標誌)建立一個單向連結串列,頭指標為L,將連結串列L中奇數值的結點重新組成一個新的連結串列NEW,並輸出新建連結串列的資訊。

第一種方法：逆向思維

#include<stdio.h>
#include<stdlib.h>
struct stu_node{
    int num;
    struct stu_node*next;
};
struct stu_node*Create_Stu_Doc();/*新建連結串列*/
struct stu_node*DeleteDoc(struct stu_node*head);/*奇數項相連就是去掉偶數項
 
*/ 
void Print_Stu_Doc(struct stu_node*head);/*遍歷*/ 


int main(void)
{
    struct stu_node*head;
    head=Create_Stu_Doc();
    head=DeleteDoc(head);
    Print_Stu_Doc(head);
}

struct stu_node*Create_Stu_Doc()
{
    struct stu_node*head,*tail,*p;
    int num;
    int size=sizeof(struct stu_node);
    head
 
=tail=NULL;
    scanf("%d",&num);
    while(num!=-1)
    {
        p=(struct stu_node*)malloc(size);
        p->num=num;
        p->next=NULL;
        if(head==NULL)
        head=p;
        else
        tail->next=p;
        tail=p;
        scanf("%d",&num);
    }
    return head;
}

 
struct stu_node*DeleteDoc(struct stu_node*head)
{
    struct stu_node*ptr1,*ptr2;
    while(head!=NULL&&head->num%2==0)
    {
        ptr1=head;
        ptr2=head->next;
        free(ptr2);
    }
    if(head==NULL)
    return NULL;
    ptr1=head;
    ptr2=head->next;
    while(ptr2!=NULL)
    {
        if(ptr2->num%2==0)
        {
            ptr1->next=ptr2->next;
            free(ptr2);
        }
        else
        ptr1=ptr2;
        ptr2=ptr1->next;
    }
    return head;
}

void Print_Stu_Doc(struct stu_node*head)
{
    struct stu_node*ptr;
    if(head==NULL)
    {
        printf("N0 Records\n");
        return;
    }
    for(ptr=head;ptr;ptr=ptr->next)
    printf("%d",ptr->num);
    printf("\n");
}

 第二種方法：正向思維

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
struct stud_node{
int num;
struct stud_node *next;
};
void Ptrint_Stu_Doc(struct stud_node *head);
int main()
{
struct stud_node *L,*tail1,*tail2,*p1,*p2,*NEW;
int num;
int size=sizeof(struct stud_node);

L=tail1=NULL;
scanf("%d",&num);
while(num!=-1){                        /*---新建連結串列L--*/
p1=(struct stud_node *)malloc(size);
p1->num=num;
p1->next=NULL;
if(L==NULL)
L=p1;
else
tail1->next=p1;
tail1=p1;
scanf("%d",&num);
}

NEW=tail2=NULL;      
p1=L;
while(p1!=NULL){
if(p1->num%2==0&&p1!=NULL){         /*--刪除連結串列L中的偶數值---*/
if(p1->next!=NULL){    
p1=p1->next;
continue;
}
else
break;
}
if(p1==NULL)         break;                   /*----將連結串列L中奇數值的結點重新組成一個新的連結串列NEW--*/
p2=(struct stud_node *)malloc(size);
p2->num=p1->num;
p2->next=NULL;
if(NEW==NULL)
NEW=p2;
else
tail2->next=p2;
tail2=p2;
p1=p1->next;
}
tail2->next=NULL;
Ptrint_Stu_Doc(NEW);
}
void Ptrint_Stu_Doc(struct stud_node *head)
{
struct stud_node *ptr;
if(head==NULL){
printf("No Records\n");
return;
}
for(ptr=head;ptr;ptr=ptr->next)
printf("%d",ptr->num);
printf("\n");
}