我無法獲得在給定節點的開頭、結尾和之后插入節點的輸出。我不太確定在 main() 中是否遺漏了什么。我無法在程式中指出我的邏輯錯誤`
#include<stdio.h>
#include<stdlib.h>
struct node{
int data;
struct node *next;
};
//Inserts at the begining
void push(struct node **head, int x){
struct node *newnode = (struct node *)malloc(sizeof(struct node));
newnode->data = x;
*head = newnode;
newnode->next = (*head);
*head = newnode;
}
//Insert at the last
void append(struct node **head, int x){
struct node *temp;
struct node* newnode = (struct node*)malloc(sizeof(struct node));
newnode->data = x;
newnode->next = 0;
if(*head == 0){
*head = newnode;
}
temp = *head;
while(temp->next != 0){
temp = temp->next;
}
temp->next = newnode;
}
//inserting at a given node
void insertAfter(struct node* temp, int x){
if(temp == NULL){
printf("previous node cannot be NULL");
}
struct node* newnode = (struct node*)malloc(sizeof(struct node));
newnode->data = x;
newnode->next = temp->next;
temp->next = newnode;
}
void printList(struct node *temp){
while(temp->next != NULL){
printf("%d",temp->data);
}
temp = temp->next;
}
int main(){
struct node *head = NULL;
append(&head,6);
push(&head, 7);
push(&head, 1);
append(&head, 4);
insertAfter(head->next, 8);
printf("Created linked list is:\n");
printList(head);
return 0;
}
`
輸出為 1 7 8 6 4
但我沒有得到任何輸出，也沒有錯誤
uj5u.com熱心網友回復：
在函式print_list中可以有一個無限回圈，因為這個陳述句
temp = temp->next;
放在while回圈之后
void printList(struct node *temp){
while(temp->next != NULL){
printf("%d",temp->data);
}
temp = temp->next;
}
該功能可以通過以下方式查找例如
void printList( const struct node *head )
{
for ( ; head != NULL; head = head->next )
printf( "%d -> ", head->data );
}
puts( "null" );
}
注意函式內的pushthis陳述句
*head = newnode;
出現兩次。
此外，這些函式也是不安全的，因為沒有檢查函式內是否成功分配了記憶體。
例如，可以通過以下方式宣告和定義函式 append
//Insert at the last
int append( struct node **head, int x )
{
struct node *newnode = malloc( sizeof( *newnode ) );
int success = newnode != NULL;
if ( success )
{
newnode->data = x;
newnode->next = NULL;
while ( *head != NULL ) head = &( *head )->next;
*head = newnode;
}
return success;
}
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