Unheadless single-chain table reversal

  1 #include <iostream>                                                                                                   2   3 using namespace std;  4   5 struct node  6 {  7     int data;  8     node *next;  9 }; 10  11  12 node *list_create(void) 13 { 14     node *head = NULL;  15     node **current = &head; 16  17     cout << "input value until -1" << endl; 18  19     int a = 0; 20     cin >> a; 21     while(a != -1) 22     { 23         *current = new node; 24         (*current)->next = NULL;  25         (*current)->data = a; 26         current = &((*current)->next); 27         cin >> a; 28     } 29  30     return head; 31 } 32  33 void list_print(const node *head) 34 { 35  36     while(head) 37     { 38         cout << "node->next is : " << head->next << " node->data is : " << head->data <<endl;  39         head = head->next; 40     } 41 } 42  43 node *node_delete(node *head, int data) 44 { 45     if(head == NULL) 46         return head; 47  48     node *current = head; 49     node *prev = head; 50  51     if(head->data == data) 52     { 53         head = head->next; 54         current->next = NULL; 55         delete current; 56         return head; 57     } 58  59  60     while(current) 61     { 62         if(current->data == data) 63             break; 64         prev = current; 65         current = current->next; 66     } 67  68     if(current) 69     { 70         prev->next = current->next; 71         current->next = NULL; 72         delete current; 73     } 74  75     return head; 76 } 77  78 void list_delete(node *head) 79 { 80     node *temp; 81     while(head) 82     { 83         temp = head;  84         head = head->next; 85         temp->next = NULL; 86         delete temp; 87     } 88 } 89  90 node* list_insert(node *head, int data) 91 { 92     node *node_new = new node; 93     node_new->data = data; 94     node_new->next = NULL; 95  96     if(head == NULL) 97     { 98         head = node_new; 99         return head;100     }101 102     if(head->data >= data)103     {104         node_new->next = head;105         head = node_new;106         return head;107     }108 109     node *prev = head;110     node *current = head;111 112     while(current)113     {114         if(current->data < data)115         {116             prev = current;117             current = current->next;118             continue;119         }120         break;121     }122 123     node_new->next = current;124   prev->next=node_new;      125     return head;126 }127 128 node *list_rev(node *head)129 {130     if(NULL == head)131         return head;132 133     node *prev = head;134     node *current = head;135     node *next = head->next;136 137 138     while(next != NULL)139     {140         current = next;141         next = current->next;142         current->next = prev;143         prev = current;144     }145 146     head->next = NULL;147     head = current;148     return head;149 }150 151 node *create_sort(void)152 {153     node * head = NULL;154     int a = 0;155     cin >> a;156     while(a != -1)157     {158         head = list_insert(head, a);159         cin >> a;160     }161 162     return head;163 }164 int main(void)165 {166     node *head;167     int num;168     head = list_create();169     list_print(head);170 171     cout << "input the delete number" << endl;172     cin >> num;173 174     head = node_delete(head, num);175 176     list_print(head);177 178     list_delete(head);179 180     head = create_sort();181 182     list_print(head);183 184     head = list_rev(head);185 186     list_print(head);   187 188     list_delete(head);189 190     return 0;191 }                                                                                                       192