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Revised Linked List (#999)
* Addition of Test to LinkedList I noticed an infinite loop when the program asks the user to "Enter the element to be inserted:", and the user enters a wrong input such as "rr". * Revised Tests * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update data_structures/linked_list.cpp Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list.cpp Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list.cpp Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list.cpp Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list.cpp Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list.cpp Co-authored-by: David Leal <halfpacho@gmail.com> * Update data_structures/linked_list.cpp Co-authored-by: David Leal <halfpacho@gmail.com> * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update data_structures/linked_list.cpp Co-authored-by: David Leal <halfpacho@gmail.com> * added documentations to functions I made a few changes although I'm not sure I covered all. * Update linked_list.cpp * function documentation Co-authored-by: David Leal <halfpacho@gmail.com> * function documentation Co-authored-by: David Leal <halfpacho@gmail.com> * function documentation * Update linked_list.cpp * removed global variable I decided to go with the parameter approach. Is line 79(Iter& ....) and others like it considered healthy code? * removed global variable * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * fixed clang errors * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * program rewrite * Update linked_list.cpp * Update linked_list.cpp * Removed extra space * Update linked_list.cpp * Delete vdoubly_linked_list.ico * added documentation * added documentation * added documentation * use of shared_ptr * use of shared_ptr * modified linked list * Update linked_list.cpp * added string header * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * fixed documentation * fixed link class * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * Update linked_list.cpp * fixed link class * fixed runtime error Co-authored-by: David Leal <halfpacho@gmail.com>
This commit is contained in:
Bolaji Boluwatife
GitHub
parent
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commit
6e77f98494
@ -1,134 +1,275 @@
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/**
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* @file
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* @brief Implementation of singly linked list algorithm.
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* @details
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* The linked list is a data structure used for holding a sequence of
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* values, which can be added, removed and displayed.
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* ### Algorithm
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* Values can be added by iterating to the end of a list(by following
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* the pointers) starting from the first link. Whichever link points to null
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* is considered the last link and is pointed to the new value.
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*
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* Values can be removed by also iterating through the list. When the node
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* containing the value is found, the node pointing to the current node is made
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* to point to the node that the current node is pointing to, and then returning
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* the current node to heap store.
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*/
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#include <iostream>
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#include <memory>
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#include <string>
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struct node {
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int val;
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node *next;
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/**
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* @namespace data_structures
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* @brief Data Structures algorithms
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*/
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namespace data_structures {
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/**
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* @namespace linked_list
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* @brief Functions for singly linked list algorithm
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*/
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namespace linked_list {
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/**
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* This function checks if the string passed consists
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* of only digits.
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* @param s To be checked if s contains only integers
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* @returns true if there are only only digits present in the string
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* @returns false if any other character is found
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*/
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bool isDigit(const std::string& s) {
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// function statements here
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for (char i : s) {
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if (!isdigit(i)) {
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return false;
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}
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}
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return true;
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}
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/**
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* A link class containing a value and pointer to another link
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*/
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class link {
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private:
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int pvalue; ///< value of the current link
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std::shared_ptr<link> psucc; ///< pointer to the next value on the list
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public:
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/**
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* function returns the integer value stored in the link.
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* @returns the integer value stored in the link.
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*/
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int val() { return pvalue; }
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/**
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* function returns the pointer to next link
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* @returns the pointer to the next link
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* */
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std::shared_ptr<link>& succ() { return psucc; }
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/**
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* Creates link with provided value and pointer to next link
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* @param value is the integer stored in the link
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*/
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explicit link(int value = 0) : pvalue(value), psucc(nullptr) {}
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};
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node *start;
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/**
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* A list class containing a sequence of links
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*/
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class list {
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private:
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std::shared_ptr<link> first; ///< link before the actual first element
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std::shared_ptr<link> last; ///< last link on the list
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public:
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/**
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* List constructor. Initializes the first and last link.
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*/
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list() {
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// Initialize the first link
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first = std::make_shared<link>();
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// Initialize the last link with the first link
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last = nullptr;
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}
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void insert(int x) {
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node *t = start;
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node *n = new node;
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n->val = x;
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n->next = NULL;
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if (start != NULL) {
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while (t->next != NULL) {
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t = t->next;
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}
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t->next = n;
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bool isEmpty();
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void push_back(int new_elem);
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void push_front(int new_elem);
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void erase(int old_elem);
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void display();
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std::shared_ptr<link> search(int find_elem);
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void reverse();
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};
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/**
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* function checks if list is empty
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* @returns true if list is empty
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* @returns false if list is not empty
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*/
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bool list::isEmpty() {
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if (last == nullptr) {
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return true;
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} else {
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start = n;
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return false;
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}
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}
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void remove(int x) {
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if (start == NULL) {
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std::cout << "\nLinked List is empty\n";
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return;
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} else if (start->val == x) {
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node *temp = start;
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start = start->next;
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delete temp;
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return;
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}
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node *temp = start, *parent = start;
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while (temp != NULL && temp->val != x) {
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parent = temp;
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temp = temp->next;
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}
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if (temp == NULL) {
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std::cout << std::endl << x << " not found in list\n";
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return;
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}
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parent->next = temp->next;
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delete temp;
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}
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void search(int x) {
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node *t = start;
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int found = 0;
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while (t != NULL) {
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if (t->val == x) {
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std::cout << "\nFound";
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found = 1;
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break;
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}
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t = t->next;
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}
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if (found == 0) {
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std::cout << "\nNot Found";
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}
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}
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void show() {
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node *t = start;
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while (t != NULL) {
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std::cout << t->val << "\t";
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t = t->next;
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}
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}
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void reverse() {
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node *first = start;
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if (first != NULL) {
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node *second = first->next;
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while (second != NULL) {
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node *tem = second->next;
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second->next = first;
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first = second;
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second = tem;
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}
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start->next = NULL;
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start = first;
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/**
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* function adds new element to the end of the list
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* @param new_elem to be added to the end of the list
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*/
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void list::push_back(int new_elem) {
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if (isEmpty()) {
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first->succ() = std::make_shared<link>(new_elem);
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last = first->succ();
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} else {
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std::cout << "\nEmpty list";
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last->succ() = std::make_shared<link>(new_elem);
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last = last->succ();
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}
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}
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/**
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* function adds new element to the beginning of the list
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* @param new_elem to be added to front of the list
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*/
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void list::push_front(int new_elem) {
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if (isEmpty()) {
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first->succ() = std::make_shared<link>(new_elem);
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last = first->succ();
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} else {
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std::shared_ptr<link> t = std::make_shared<link>(new_elem);
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t->succ() = first->succ();
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first->succ() = t;
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}
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}
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/**
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* function erases old element from the list
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* @param old_elem to be erased from the list
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*/
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void list::erase(int old_elem) {
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if (isEmpty()) {
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std::cout << "List is Empty!";
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return;
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}
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std::shared_ptr<link> t = first;
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std::shared_ptr<link> to_be_removed = nullptr;
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while (t != last && t->succ()->val() != old_elem) {
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t = t->succ();
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}
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if (t == last) {
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std::cout << "Element not found\n";
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return;
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}
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to_be_removed = t->succ();
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t->succ() = t->succ()->succ();
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to_be_removed.reset();
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if (t->succ() == nullptr) {
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last = nullptr;
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}
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}
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/**
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* function displays all the elements in the list
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* @returns 'void'
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*/
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void list::display() {
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if (isEmpty()) {
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std::cout << "List is Empty!";
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return;
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}
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std::shared_ptr<link> t = first;
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while (t->succ() != nullptr) {
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std::cout << t->succ()->val() << "\t";
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t = t->succ();
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}
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}
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/**
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* function searchs for @param find_elem in the list
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* @param find_elem to be searched for in the list
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*/
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std::shared_ptr<link> list::search(int find_elem) {
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if (isEmpty()) {
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std::cout << "List is Empty!";
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return nullptr;
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}
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std::shared_ptr<link> t = first;
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while (t != last && t->succ()->val() != find_elem) {
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t = t->succ();
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}
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if (t == last) {
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std::cout << "Element not found\n";
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return nullptr;
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}
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std::cout << "Element was found\n";
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return t->succ();
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}
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} // namespace linked_list
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} // namespace data_structures
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/**
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* Main function:
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* Allows the user add and delete values from the list.
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* Also allows user to search for and display values in the list.
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* @returns 0 on exit
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*/
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int main() {
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int choice, x;
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data_structures::linked_list::list l;
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int choice = 0;
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int x = 0;
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std::string s;
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do {
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std::cout << "\n1. Insert";
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std::cout << "\n2. Delete";
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std::cout << "\n3. Search";
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std::cout << "\n4. Print";
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std::cout << "\n5. Reverse";
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std::cout << "\n0. Exit";
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std::cout << "\n\nEnter you choice : ";
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std::cin >> choice;
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switch (choice) {
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case 1:
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std::cout << "\nEnter the element to be inserted : ";
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std::cin >> x;
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insert(x);
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break;
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case 2:
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std::cout << "\nEnter the element to be removed : ";
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std::cin >> x;
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remove(x);
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break;
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case 3:
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std::cout << "\nEnter the element to be searched : ";
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std::cin >> x;
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search(x);
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break;
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case 4:
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show();
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std::cout << "\n";
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break;
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case 5:
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std::cout << "The reversed list: \n";
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reverse();
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show();
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std::cout << "\n";
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break;
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case 1:
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std::cout << "\nEnter the element to be inserted : ";
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std::cin >> s;
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if (data_structures::linked_list::isDigit(s)) {
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x = std::stoi(s);
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l.push_back(x);
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} else {
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std::cout << "Wrong Input!\n";
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}
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break;
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case 2:
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std::cout << "\nEnter the element to be removed : ";
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std::cin >> s;
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if (data_structures::linked_list::isDigit(s)) {
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x = std::stoi(s);
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l.erase(x);
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} else {
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std::cout << "Wrong Input!\n";
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}
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break;
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case 3:
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std::cout << "\nEnter the element to be searched : ";
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std::cin >> s;
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if (data_structures::linked_list::isDigit(s)) {
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x = std::stoi(s);
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std::shared_ptr<data_structures::linked_list::link> found =
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l.search(x);
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} else {
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std::cout << "Wrong Input!\n";
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}
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break;
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case 4:
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l.display();
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std::cout << "\n";
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break;
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default:
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std::cout << "Invalid Input\n" << std::endl;
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break;
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}
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} while (choice != 0);
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return 0;
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}
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