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  1. #include <iostream>
  2. #include <fstream>
  3.  
  4. using namespace std;
  5.  
  6. struct Node {
  7.        int info;
  8.        struct Node *next;
  9.        struct Node *prev;
  10. };
  11.  
  12. //globals
  13. Node *front = NULL, *back = NULL;
  14.  
  15. void add_to_right(int);
  16. void add_after(int,int);
  17. void add_before(int,int);
  18. void remove_node(int);
  19. void display_from_left_to_right();
  20. void display_from_right_to_left();
  21.  
  22. int main() {
  23.     int whichnode, whatvalue;
  24.     int removenode;
  25.  
  26.     for(int i=1;i<=9;i++)
  27.         add_to_right( i );
  28.  
  29.     display_from_left_to_right(); 
  30.     display_from_right_to_left();
  31.  
  32.  
  33.     cout<<endl;
  34.     cout<<"insert after node=";
  35.     cin>>whichnode;
  36.     cout<<"which one value=";
  37.     cin>>whatvalue;
  38.     add_after(whichnode, whatvalue);
  39.     display_from_left_to_right(); 
  40.  
  41.  
  42.     cout<<endl;
  43.     cout<<"insert before node=";
  44.     cin>>whichnode;
  45.     cout<<"which one value=";
  46.     cin>>whatvalue;
  47.     add_before(whichnode, whatvalue);
  48.     display_from_left_to_right(); 
  49.  
  50.     cout<<endl;
  51.     cout<<"Node to remove=";
  52.     cin>>removenode;
  53.     remove_node(removenode);
  54.     display_from_left_to_right(); 
  55.  
  56.  
  57.     return (0);
  58. };
  59.  
  60. void add_to_right(int whatvalue) {
  61.  
  62.      struct Node *c;
  63.  
  64.      if(front == NULL) {
  65.  
  66.         c = new Node;
  67.         c->info = whatvalue;
  68.         c->next = c->prev = NULL; 
  69.         front = back = c;
  70.  
  71.      } else {
  72.  
  73.         c = new Node;
  74.         c->info = whatvalue;
  75.         c->next = NULL;
  76.         c->prev = back;
  77.         back->next = c; 
  78.         back = c;
  79.      }
  80.  
  81. };
  82.  
  83. void add_after(int whichone, int whatvalue) {
  84.  
  85.      struct Node *c = front, *p;
  86.  
  87.      if(back->info == whichone) {
  88.  
  89.        p = new Node;
  90.        p->info = whatvalue;
  91.        p->next = NULL;
  92.        p->prev = back;
  93.        back->next = p; 
  94.        back = p;
  95.  
  96.      } else {
  97.  
  98.        while(c->info != whichone) c = c->next;
  99.  
  100.        p = new Node;
  101.        p->info = whatvalue;
  102.        p->next = c->next;
  103.        p->prev = c; 
  104.        c->next->prev = p;
  105.        c->next = p;
  106.      }     
  107. };
  108.  
  109. void remove_node(int removenode) {
  110.  
  111.      struct Node *removal, *c;
  112.  
  113.  
  114.      if(front->info == removenode) {
  115.  
  116.         removal = front;
  117.  
  118.         front = front->next;
  119.         front->prev = 0;
  120.  
  121.         delete removal;    
  122.  
  123.      } else if(front->info != removenode && back->info != removenode){
  124.  
  125.        c = front;
  126.  
  127.        while(c->info != removenode) c = c->next;
  128.  
  129.        c->next->prev = c->prev;
  130.        c->prev->next = c->next;
  131.  
  132.        delete c;       
  133.  
  134.       } else if(back->info == removenode) {
  135.  
  136.        removal = back;
  137.  
  138.        back = back->prev;
  139.        back->next = NULL;
  140.  
  141.        delete removal; 
  142.      }
  143. };
  144.  
  145. void display_from_left_to_right() {
  146.  
  147.      struct Node *c;
  148.  
  149.      cout<<endl;
  150.  
  151.      for(c = front; c; c = c->next) 
  152.  
  153.          cout<<c->info<<" ";      
  154. };
  155.  
  156. void display_from_right_to_left() {
  157.  
  158.      struct Node *c = back;
  159.  
  160.      cout<<endl; 
  161.  
  162.      for(c = back; c; c = c->prev) 
  163.  
  164.          cout<<c->info<<" ";     
  165. };
  166.  
  167. void add_before(int whichnode,int whatvalue) {
  168.  
  169.     struct Node *p,*c;
  170.  
  171.     if(front->info == whichnode) {
  172.  
  173.        p = new Node;
  174.        p->info = whatvalue;
  175.        p->next = front;
  176.        front->prev = p;  
  177.        front = p; 
  178.  
  179.     } else {
  180.  
  181.        c = front;
  182.  
  183.        while(c->next->info != whichnode) c = c->next;
  184.  
  185.        p = new Node;
  186.        p->info = whatvalue;
  187.        p->next = c->next;
  188.        p->prev = c;
  189.        c->next->prev = p;
  190.        c->next = p;
  191.     }
  192. }
Success #stdin #stdout 0.01s 5296KB
comments (?)
stdin
copy 
3
9999
8
88888
5
stdout
copy 
1 2 3 4 5 6 7 8 9 
9 8 7 6 5 4 3 2 1 
insert after node=which one value=
1 2 3 9999 4 5 6 7 8 9 
insert before node=which one value=
1 2 3 9999 4 5 6 7 88888 8 9 
Node to remove=
1 2 3 9999 4 6 7 88888 8 9
https://ideone.com/gL8ZqO
Doubly Linked List
language:
C++ (gcc 8.3)
created:
329 days ago
visibility:
secret

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