View difference between Paste ID: 5BWZnT9F and reSQjZCW

 /* error in remove */
 
 #include<cstdio>
 #include<iostream>
 using namespace std;
 
 void push(int x);
 void pop();
 void search(int x);
 void update(int oldvalue,int newvalue);
 void remove(int num);
 //void insert(int afterwhich,int numbertoinsert);
 
 typedef struct alvi
 {
     int data;
     struct alvi *prev;
     struct alvi *next;
 }node;
 
 node *head = NULL;
 node *tail = NULL;
 
 int main(void)
 {
     int choice,push_number,search_number,remove_number,olds,news;
     while(1)
     {
         printf("Choose : 1 to push,2 to pop,3 to search,4 to update,5 to remove,6 to quit\n");
         scanf("%d",&choice);
         switch(choice)
         {
             case 1:
                 printf("Enter number to push : ");
                 scanf("%d",&push_number);
                 push(push_number);
                 break;
             case 2:
                 pop();
                 break;
             case 3:
                 printf("Enter number to search : ");
                 scanf("%d",&search_number);
                 search(search_number);
                 break;
             case 4:
                 printf("Enter a old value :");
                 scanf("%d",&olds);
                 printf("Enter a new value :");
                 scanf("%d",&news);
                 update(olds,news);
                 break;
             case 5:
                 printf("Enter a number to remove : ");
                 scanf("%d",&remove_number);
                 remove(remove_number);
                 break;
             case 6:
                 return 0;
             default:
                 printf("Wrong input \n");
                 break;
 
         }
     }
     return 0;
 }
 void push(int x)
 {
     node *newNode = new node();
     newNode->data = x;
     if(head==NULL)
     {
         cout<<"First node pushed"<<endl;
         newNode->prev=NULL;
         newNode->next=NULL;
         head=newNode;
         tail=newNode;
     }
     else
     {
         cout<<"other node pushed"<<endl;
         head->prev=newNode;
         newNode->next=head;
         head=newNode;
     }
 }
 void pop()
 {
     node *cursor;
     cursor = tail;
     while(cursor!=NULL)
     {
         cout<<cursor->data<<" ";
         cursor=cursor->prev;
     }
     cout<<endl;
 }
 void search(int x)
 {
     node *cursor1;
     cursor1 = head;
     int flag=0;
     int counter = 1;
     while(cursor1!=NULL)
     {
         if(cursor1->data==x)
         {
             flag=1;
             cout<<"found"<<endl;;
             cout<<"element number : "<<counter<<endl;
             break;
         }
         cursor1=cursor1->next;
         counter++;
     }
     if(flag==0)
     {
         cout<<"not found"<<endl;
     }
 }
 void update(int oldvalue,int newvalue)
 {
     node *cursor2;
     cursor2 = head;
     int flag=0;
     //int counter = 1;
     while(cursor2!=NULL)
     {
         if(cursor2->data==oldvalue)
         {
             flag=1;
             cursor2->data=newvalue;
             break;
         }
         cursor2=cursor2->next;
         //counter++;
     }
     if(flag==0)
     {
         cout<<"not found"<<endl;
     }
 }
 void remove(int num)
 {
     node *cursor3;
     cursor3 = head;
     int flag=0;
     //int counter = 1;
     while(cursor3!=NULL)
     {
         if(cursor3->data==num && (cursor3->next==NULL || cursor3->prev==NULL ))
         {
             flag=2;
             if( (cursor3->prev!=NULL && cursor3->next==NULL ) )
             {
                 flag=3;
                 cursor3->prev=NULL;
                 break;
             }
             if( (cursor3->prev==NULL && cursor3->next!=NULL ) )
             {
                 flag=4;
                 cursor3->next=NULL;
                 break;
             }
             if( (cursor3->prev==NULL && cursor3->next==NULL ) )
             {
                 flag=5;
             }
 
 
 
 
             if(flag==3)
             {
 
             }
             if(flag==4)
             {
 
             }
             if(flag==5)
             {
 
             }
 
 
         }
         if(cursor3->data==num && cursor3->next!=NULL && cursor3->prev!=NULL   )
         {
             flag=1;
             (cursor3->prev)->next = cursor3->next;
             (cursor3->next)->prev = cursor3->prev;
             break;
         }
         cursor3=cursor3->next;
         //counter++;
     }
     cout<<flag;
     if(flag==0)
     {
         cout<<"not found"<<endl;
 
     }
 }
 /*
 void insert(int afterwhich,int numbertoinsert)
 {
     node *cursor4;
     cursor4 = head;
     int flag=0;
     //int counter = 1;
     while(cursor4!=NULL)
     {
         if(cursor4->data==afterwhich)
         {
             flag=1;
 
             break;
         }
         cursor4=cursor4->next;
         //counter++;
     }
     if(flag==0)
     {
         cout<<"not found"<<endl;
     }
 }
 */