单链表的基本操作（创建，删除，插入，逆置）

Posted 2021-01-07 cantredo

代码鲁棒性较差，之后补充注释以及减少BUG增加可读性。

#include <iostream>
#include <vector>
#include <cstring>
#include <malloc.h>

using namespace std ;

typedef struct Node{
    int data ;
    struct Node *next ;
}node , *Lnode ;

int Linklist_length( node *head ){
    node *p = (node*)malloc(sizeof(node)) ;
    int len = 0 ;
    while ( p ){
        p = p->next ;
        len ++ ;
    }
    return len ;
}

Lnode Link_reverse_head( node *head ){
    node *p = head->next ;
    head->next = NULL ;
    node *q ;
    while ( p ){
        q = p ;
        p = p->next ;
        q->next = head->next ;
        head->next = q ;
    }
    return head ;
}

Lnode Linklist_insert( int pos , int num , node *head ){
    node *index = head ;
    for ( int i = 0 ; i < pos ; i ++ ){
        index = index->next ;
    }
    node *p = (node*)malloc(sizeof(node)) ;
    p->data = num ;
    p->next = index->next ;
    index->next = p ;
    return head ;
}

Lnode Linklist_delete( int pos , node *head ){
    node *index = head ;
    for ( int i = 1 ; i < pos ; i ++ ){
        index = index->next ;
    }
    node *p = index->next ;
    index->next = p->next ;
    p->next = NULL ;
    free( p ) ;
    return head ;
}

Lnode Creat_from_head( int count ){
    node *head = (node*)malloc(sizeof(node)) ;
    head->next = NULL ;
    int num ;
    while ( count -- && cin >> num ){
        node *p = (node*)malloc(sizeof(node)) ;
        p->data = num ;
        p->next = head->next ;
        head->next = p ;
    }
    return head ;
}

Lnode Creat_from_last( int count ){
    node *head = (node*)malloc(sizeof(node)) ;
    head->next = NULL ;
    int num ;
    node *index = head ;
    while ( count -- && cin >> num ){
        node *p = (node*)malloc(sizeof(node)) ;
        p->data = num ;
        index->next = p ;
        index = p ;
    }
    index->next = NULL ;
    return head ;
}

void output( node *head ){
    node *p = head->next ;
    while ( p ){
        cout << p->data << " " ;
        p = p->next ;
    }
    cout << endl ;
    return ;
}

int main(){
    int num ;
    cin >> num ;
    node *index_creat = Creat_from_last( num ) ;
    output( index_creat ) ;
    int pos , number ;
    cin >> pos >> number ;
    node *index_insert = Linklist_insert( pos , number , index_creat ) ;
    output( index_insert ) ;
    cin >> pos ;
    node *index_delete = Linklist_delete( pos , index_creat ) ;
    output( index_delete ) ;
//    int len = Linklist_length( index_creat ) ;
    node *index_reverse = Link_reverse_head( index_creat ) ;
    output( index_reverse ) ;
    return 0 ;
}