Question

基本上插入中间工作，但是当我想插入一个值作为第一个（在开始时）它插入但我还会显示一个地址（列表头的数据部分）。

为了使listhead指向新元素，我需要修改什么？

#include <stdio.h>
#include <conio.h>
struct entry {
    int value;
    struct entry *next;
};

//X position struct u want to target
struct entry *insertentry(struct entry *new_entry, struct entry *x){
    int data;


    printf("Enter a value for your new entry\n");
    scanf("%i",&data);
    new_entry->value=data;
    new_entry->next=x->next;
    x->next=&(*new_entry);
    return new_entry;
};

int main (void)
{
    struct entry n1, n2, n3,*n4,n5;
    struct entry list_head, *list_pointer=&list_head;
    list_head.next=&n1;
    n1.value = 100;
    n1.next = &n2;
    n2.value = 200;
    n2.next = &n3;
    n3.value = 300;
    n4=insertentry(&n5,&list_head);
    n3.next = (struct entry *) 0; // Mark list end with null pointer
    while ( list_pointer != (struct entry *) 0 ) {
        printf ("%i\n", list_pointer->value);
        list_pointer = list_pointer->next;
    }
    printf("%i\n",n5.value);

    getch();
    return 0;
}

Answer 1

出于某种原因，我没有conio.h所以我在这里删除它。您错过了将变量正确设置为col-sm-6。

此代码应该：

list_pointer=&n1;

Answer 2

它不显示地址，而是显示list_head.next的未初始化值

int main (void)
{
    struct entry n1, n2, n3,*n4,n5;
    struct entry list_head, *list_pointer=list_head.next;

    list_pointer.value = 0; // another way without discarding list_pointer content
    list_head.next=&n1;
    n1.value = 100;
    n1.next = &n2;
    n2.value = 200;
    n2.next = &n3;
    n3.value = 300;
    ...
}

Answer 3

现在它运行正常，但我已经手动完成了问题，＆＃34;如何在它之前插入节点的功能＆＃34;看起来像

#include <stdio.h>
#include <conio.h>
struct entry {
 int value;
 struct entry *next;

};
//X struct u want to target
struct entry insertentry(struct entry *new_entry, struct entry *x){
int data;

printf("Enter a value for your new entry");
scanf("%i",&data);
new_entry->value=data;
new_entry->next=x->next;
x->next=&(*new_entry);
return *new_entry;};

int main (void)
{struct entry n1, n2, n3,n4,n5,list_head;
struct entry *list_pointer;
n1.value = 100;
list_head.next=&n1;

n4=insertentry(&n5,&list_head);
list_pointer=&n4;
n1.next = &n2;
n2.value = 200;
n2.next = &n3;
n3.value = 300;

n3.next = (struct entry *) 0; // Mark list end with null pointer
while ( list_pointer != (struct entry *) 0 ) {
printf ("%i\n", list_pointer->value);
list_pointer = list_pointer->next;
}
printf("%i\n",n5.value);


getch();
return 0;
}

C中的链表插入功能问题

3 个答案: