C++ Program Problem - Tree

This is a discussion on C++ Program Problem - Tree within the C++ Programming forums, part of the General Programming Boards category; I have been having some difficulty with implementing a program that makes a LCRS Binary Tree from the users input. ...

  1. #1
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    Sep 2011
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    21

    Question C++ Program Problem - Tree

    I have been having some difficulty with implementing a program that makes a LCRS Binary Tree from the users input. I need to have the program implement insertion, search, height, and preorder. So far I have gotten the insertion part to work, or at least it doesn't crash when inserting values . The problem is with my search function, it works if the value I'm looking for is the root node, but if it's deeper in the tree, it keeps returning false, earlier I was getting Access Errors, but I seemed to have resolved that bug. If anyone sees the error in my function, I would greatly appreciate the help. Thanks!

    [functions]
    Code:
    1. #include "BST.h"
    2. #include <cstdlib>
    3. #include <iostream>
    4. using namespace std;
    5. int Tree::command(string s) {
    6. if (s == "insert") return 1;
    7. if (s == "search") return 2;
    8. if (s == "preorder") return 3;
    9. if (s == "height") return 4;
    10. if (s == "quit") return 5;
    11. return -1;
    12. }
    13. bool Tree::insert(int value) {
    14. if (root == NULL) {
    15. root = new Node(value);
    16. cout<<"Root: "<<root->value<<endl;
    17. return true;
    18. } else
    19. return root->insert(value);
    20. }
    21. bool Node::insert(int value) {
    22. if (value = this->value) return true;
    23. else {
    24. if (this->child == NULL) {
    25. this->child = new Node(value);
    26. return true;
    27. } else {
    28. if (value < this->value) {
    29. if (this->value < this->child->value && this->child->sibling == NULL) {
    30. Node *s = new Node(value);
    31. s->sibling = this->child;
    32. this->child = s;
    33. return true;
    34. }
    35. if (this->value > this->child->value && this->child->sibling == NULL)
    36. return this->child->insert(value);
    37. if (this->child->sibling != NULL)
    38. return this->child->insert(value);
    39. }
    40. if (value > this->value) {
    41. if (this->value < this->child->value && this->child->sibling == NULL) {
    42. return this->child->insert(value);
    43. }
    44. if (this->value > this->child->value && this->child->sibling == NULL) {
    45. this->child->sibling = new Node(value);
    46. return true;
    47. }
    48. if (this->child->sibling != NULL) {
    49. return this->child->sibling->insert(value);
    50. }
    51. }
    52. }
    53. }
    54. }
    55. bool Tree::search(int value) {
    56. if (root == NULL)
    57. {
    58. cout<<"is null"<<endl;
    59. return false;
    60. }
    61. else{
    62. if(root->value == value) return true;
    63. else
    64. return root->search(value);
    65. }
    66. }
    67. bool Node::search(int value)
    68. {
    69. if (this->value == value) return true;
    70. else
    71. {
    72. if(this->child != NULL || this->sibling != NULL)
    73. {
    74. if(value > this->value && this->sibling != NULL)
    75. return this->sibling->search(value);
    76. if(value > this->value && this->sibling == NULL)
    77. return false;
    78. if(value < this->value && this->child != NULL)
    79. return this->child->search(value);
    80. if(value < this->value && this->child == NULL)
    81. return false;
    82. }
    83. else return false;
    84. }
    85. }
    [header]
    Code:
    1. #include <cstdlib>
    2. #include <string>
    3. using namespace std;
    4. class Node {
    5. public:
    6. int value;
    7. Node* child;
    8. Node* sibling;
    9. Node(int value) {
    10. this->value = value;
    11. child = NULL;
    12. sibling = NULL;
    13. }
    14. bool insert(int );
    15. bool search(int);
    16. };
    17. class Tree {
    18. private:
    19. Node* root;
    20. public:
    21. Tree() {
    22. root = NULL;
    23. }
    24. bool insert(int );
    25. int height(Tree *);
    26. bool search(int );
    27. void preorder(Tree *);
    28. int command(string);
    29. };

  2. #2
    Algorithm Dissector iMalc's Avatar
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    New Zealand
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    Check line 22, there's an obvious bug there which will be the source of your problems.

    Note that you are shooting your self in the foot by not using proper indentation.
    Try and avoid using "this->" everywhere, it just clutters up the code. If you rename the local variables to not clash with the names of your member variables, then you can easily achieve this and it will make things so much nicer to read.
    Your insert function is also very large, It can be done in a lot less code that than, so you're probably overthinking it a little.
    My homepage
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