edit, I'll try to give a better exemple:
first I'll tell your about the program:
basicly, there' two phases, the first is inserting the words (works perfectly fine)
struct trieLeaf {
keyType age = 1;
};
class Trie
{
private:
dataType character;
trieLeaf *leaf = nullptr;
class Trie **alphabet = nullptr;
int main()
{
string input;
Trie dictionary('\0');
while (getline(cin, input) && input[0] != '.')
{
dictionary.analyzeText(input);
}
while (getline(cin, input) && input[0] != '.')
{
dictionary.approxFind(input);
}
system("pause>null");
}
second phase is searching for words, if words is found then I need to reduce the number of times it has been added by 1.
if number of times it has been added is 0, then I remove it.
void Trie::approxFind(string &word)
{
int index = 0;
string result;
Trie *curr;
if (curr=find(word))
{
cout << curr->leaf->age << endl;
curr->leaf->age -= 1;
if (curr->leaf->age == 0)
{
remove(word);
}
}
else
{
result = approximate(word);
cout << "Did you mean " << result << "?\n";
}
}
Trie* Trie::find(const string &word)
{
int index = 0;
Trie *curr = this;
while (word[index] != '\0')
{
if (curr->alphabet[word[index] - 'a'] != nullptr)
{
curr = curr->alphabet[word[index++] - 'a'];
}
else
{
return (nullptr);
}
}
if (curr->leaf != nullptr)
{
return (curr);
}
}
void Trie::remove(const string &word)
{
int index = 0;
Trie *curr = this, **tempArr, *temp;
while (word[index] != '\0')
{
tempArr = curr->alphabet;
temp = curr;
curr = curr->alphabet[word[++index] - 'a'];
if (!isArrEmpty(tempArr))
{
delete(tempArr);
}
delete(temp);
temp = nullptr;
}
}
bool Trie::isArrEmpty(Trie **alphabet)
{
for (int index = 0; index < 26; index++)
{
if (!alphabet[index])
{
return (true);
}
}
return(false);
}
TempArr in isArrEmpty is losing the object it's pointing to when passing onto the funcion.
I hope it gives a better idea why
Related
I have been working on this assignment for sometime and cannot figure out what is causing the segmentation fault, any help would be appreciated, here is a copy of my two files!
I am also in the process of fixing my inFile setup, but I would rather focus on that after the fact of the segmentation error.
#include <iostream>
#include <fstream>
#include <string>
#include <list>
#include "source.cpp"
using namespace std;
void scanFile(string fileName);
void printActors(string movie);
void printShows(string actor);
const int MAX_LINE = 128;
int movies = 0;
BST tree;
int main(){
// Scan file
scanFile("tvDB.txt");
// Print all the show titles
cout << "All show titles:" << endl;
tree.displayShows();
cout << endl; // Whitespace
// Print actors /w given show
cout << "Actors from 'The Saint'" << endl;
printActors("The Saint");
// Print show /w given actor
printShows("Tim Conway");
// Print from decade
return 0;
}
// Trims the line removing all excess whitespace before and after a sentence
string isolateLine(string line)
{
int index = 0, start = 0, end = 0;
//Get the start of the line
for(int i = 0; i < line.length(); i++)
{
if(line[i] != ' ' && line[i] != '\t')
{
start = i;
break;
}
}
// Get the end of the line
for(int x = line.length(); x >= 0; x--)
{
if(line[x] != ' ' && line[x] != '\t')
{
end = x;
break;
}
}
// Trim line
line = line.substr(start, end);
return line;
}
// A boolean that returns if the tree is blank, useful for skipping a line and continuing to search for a movie
bool blankLine(string line){
for(int i = 0; i < line.length(); i++)
{
if(line[i] != ' ' && line[i] != '\t')
{
return false;
}
}
return true;
}
// Prints all the shows an actor has starred in
void printShows(string actor){
cout << "Shows with [" << actor << "]:" << endl;
tree.displayActorsShows(actor);
cout << endl; // whitespace
}
// Prints all the actors in a particular movie
void printActors(string show)
{
cout << " Actors for [" << show << "]" << endl;
tree.displayActors(show);
cout << endl;
}
// Scans the fild and categorizes every line of data into the proper categories of the show
void scanFile(string fileName)
{
ifstream inFile;
inFile.open("tvDB.txt");
list <string> actors;
string line = "";
string title = "";
string year = "";
while(getline(inFile, line))
{
line = isolateLine(line);
if(!blankLine(line))
{
// Get movie title
if(line.find('(') != std::string::npos)
{
title = line.substr(0, line.find('(')-1);
}
// Get movie year
if (line.find('(') != std::string::npos) {
year = line.substr(line.find('(') + 1, line.find(')'));
year = year.substr(0, year.find(')'));
}
// Add to actors list
actors.push_back(line);
}
else
{
if(!actors.empty()) // pops the title
{
actors.pop_front();
}
}
tree.insert(title, year, actors);
actors.clear();
movies++;
}
}
and
#include <iostream>
#include <list>
using namespace std;
class BST
{
// Defines the main components of the node object, as well as refrences the left and right elements
struct node
{
string show;
string year;
string genre;
string URL;
list <string> actors;
node*left;
node*right;
};
node* root;
// Deletes all the nodes of the tree
node* makeEmpty(node* t)
{
if(t == NULL)
{
return NULL;
}
else
{
makeEmpty(t->left);
makeEmpty(t->right);
delete t;
}
return NULL;
}
// Inserts a node in the tree
node* insert(string x, string year, list<string> actors, node* t)// DO not include Genrem or URL
{
if(t == NULL)
{
t = new node;
t->show = x;
t->year = year;
t->actors = actors;
t->left = t->right = NULL;
}
else if(x < t-> show)
{
t->left = insert(x, year, actors, t->left);
}
else if(x > t-> show)
{
t->right = insert(x, year, actors, t->left);
}
else
{
return t;
}
}
//Finds the minimum most node to the left
node* findMin(node* t)
{
if(t == NULL)
{
return NULL;
}
else if(t->left == NULL)
{
return t;
}
else
{
return findMin(t->left);
}
}
// Finds the maximum most node to the right
node* findMax(node* t)
{
if(t == NULL)
{
return NULL;
}
else if(t->right == NULL)
{
return t;
}
else
{
return findMax(t->right);
}
}
// Finds a node with the given parameters
node* find(node* t, string x )
{
if(t == NULL)
{
return NULL;
}
else if(x.at(0) < t-> show.at(0))
{
return find(t->left, x);
}
else if(x.at(0) > t->show.at(0))
{
return find(t->right, x);
}
else
{
return t;
}
}
// Prints out the shows inorder
void inorder(node* t)
{
if(t == NULL)
{
// Do nothing
}
else
{
inorder(t->left);
cout << "- " << t->show << endl;
inorder(t->right);
}
}
// Prints the shows of a given actor
void findShow(node* t, string person, list<string> &list)
{
if(t == NULL)
{
// Do nothing
}
else
{
while(!t->actors.empty())
{
if(t->actors.front() == person)
{
list.push_front(t->show);
break;
}
t->actors.pop_front();
}
findShow(t->left, person, list);
findShow(t->right, person, list);
}
}
// Prints the shows within a given year
void findYear(node* t, string year, list<string> &list)
{
if(t == NULL)
{
// Do nothing
}
else
{
if(t->year == year)
{
list.push_front(t->show);
}
findYear(t->left, year, list);
findYear(t->right, year, list);
}
}
public:
BST()
{
root = NULL;
}
~BST()
{
root = makeEmpty(root);
}
// Public calls to modify the tree
// Inserts a node with the given parametersremove
void insert(string x, string year, list<string> actors)
{
root = insert(x, year, actors, root);
}
// Removes a node with the given key
// void remove(string x, node* t)
// {
// root = remove(x, root);
// }
// Displays all shows within the tree
void displayShows()
{
inorder(root);
}
// Displays all the actors with a given show
void displayActors(string show)
{
root = find(root, show);
if(root != NULL) // THIS LINE
{
list<string> temp = root-> actors;
while(!temp.empty())
{
cout << "- " << temp.front() << endl;
temp.pop_front();
}
}
else
{
cout << "root is NULL." << endl;
}
}
// Displays the shows of a given actor
void displayActorsShows(string actor)
{
list<string> show;
findShow(root, actor, show);
while(!show.empty())
{
cout << "- " << show.front() << endl;
show.pop_front();
}
}
// Searches the tree with the given node
void search(string x)
{
root = find(root, x);
}
};// end of class
I would suggest using a debugger (like GDB for unix or the VisualStudioBuildIn Debugger). There the SEG Fault is indicated in which variable the seg fault will be.
Also look out for correct initialized pointers (at least with = nullptr)
Btw: try to use nullptr instead of NULL, since it is not typesafe to use NULL.
Here is why: NULL vs nullptr (Why was it replaced?)
Disclaimer: This is homework and I am pretty much a complete beginner in programming (only took an intro class to C a few years ago). If it matters, this is from a Competitive Programming class. I appreciate all feedback besides on the question itself like good programming practices, naming conventions...etc. I am new to coding, but love it and want to improve.
Consider n lists that are initialized with a single member that corresponds to its list number, i.e.:
#1: 1
#2: 2
#3: 3
...
Input:
First line contains n m where 1 ≤ n ≤ 1000000, 1 ≤ m ≤ 2000000;
Followed by m lines of k a b, where k is either 0 or 1 and denotes the type of manipulation:
k = 0: find member a and move from its position to behind member b
k = 1: move the entire list of #a list and place it behind the #b list
Output:
Print the lists in order after all the commands are executed. The question specifically states no whitespaces at the end of each line.
What I've tried:
#include <iostream>
#include <sstream>
#include <vector>
#include <ctime>
using namespace std;
class List {
private:
struct Node {
int data;
Node *next;
};
Node *head;
public:
List() {
head = NULL;
}
Node *GetHead() {
return head;
}
Node *GetPrevNode(int value) { // Gets the previous node to the node I am trying to move
Node *temp, *peek;
temp = head;
peek = temp->next;
if (head->data == value)
return head;
else {
while (peek != NULL) {
if (peek->data == value) {
return temp;
}
else {
temp = temp->next;
peek = temp->next;
}
}
return NULL;
}
return NULL;
}
Node *GetNode(int value) { // Gets the actual node I'm trying to move
Node *temp;
temp = head;
while (temp != NULL) {
if (temp->data == value) {
return temp;
}
else {
temp = temp->next;
}
}
return NULL;
}
void PushNode(int value) {
Node *temp = new Node;
temp->data = value;
temp->next = NULL;
if (head == NULL) {
head = temp;
}
else {
head->next = temp;
}
}
void MoveNode(Node *prevFrom, int value, Node *dest) { // called on the FROM list
Node *tempDestNext, *from;
tempDestNext = dest->next;
if (prevFrom->data == value) {
from = prevFrom;
}
else {
from = prevFrom->next;
}
//different cases
if (dest->next == from) {
return;
}
else if (from->next == dest) {
from->next = dest->next;
dest->next = from;
if (from == prevFrom) {
head = dest;
}
else {
prevFrom->next = dest;
}
}
else {
Node *tempFromNext;
tempFromNext = from->next;
dest->next = from;
if (from == head) {
head = tempFromNext;
}
else {
prevFrom->next = tempFromNext;
}
from->next = tempDestNext;
}
}
void ConcList(Node *headFrom) { // called on the DESTINATION list
if (head == NULL) {
head = headFrom;
}
else {
Node *temp;
temp = head;
while (temp != NULL) {
if (temp->next == NULL) {
temp->next = headFrom;
break;
}
else {
temp = temp->next;
}
}
}
}
void PrintList() {
Node *temp;
temp = head;
while (temp != NULL) {
cout << " " << temp->data;
temp = temp->next;
}
}
};
struct Move {
int type, from, to;
};
void MarkNodePos(vector<int> &NodePos, int type, int from, int to) { // record on which list a node is
switch (type) {
case 0:
NodePos[from - 1] = NodePos[to - 1];
break;
case 1:
for (int i = 0; i < NodePos.size(); i++) {
if (NodePos[i] == (from - 1)) {
NodePos[i] = (to - 1);
}
}
break;
}
}
int RandomNum(int min, int max) {
int range = max - min + 1;
int num = rand() % range + min;
return num;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0); // my teacher told us to include this code for speed optimization
int n, m;
cin >> n >> m;
cin.ignore();
vector<List> line;
for (int i = 0; i < n; i++) {
List temp;
temp.PushNode(i + 1);
line.push_back(temp);
}
vector<int> NodePos;
for (int i = 0; i < n; i++) {
NodePos.push_back(i);
}
string instrc;
Move step;
srand(time(NULL));
for (int i = 0; i < m; i++) {
int mode = 0; // switch between input and testing mode
switch (mode) {
case 0: {
getline(cin, instrc);
stringstream ss(instrc);
ss >> step.type >> step.from >> step.to;
break;
}
case 1:
stringstream ss;
ss << RandomNum(0, 1) << " " << RandomNum(1, n) << " " << RandomNum(1, n);
ss >> step.type >> step.from >> step.to;
cout << step.type << " " << step.from << " " << step.to << endl;
break;
}
if (step.from != step.to) {
switch (step.type) {
case 0:
int from, to;
from = NodePos[step.from - 1];
to = NodePos[step.to - 1];
line[from].MoveNode(line[from].GetPrevNode(step.from), step.from, line[to].GetNode(step.to));
MarkNodePos(NodePos, step.type, step.from, step.to);
break;
case 1:
if (line[step.from - 1].GetHead() != NULL) {
line[step.to - 1].ConcList(line[step.from - 1].GetHead());
List clear;
line[step.from - 1] = clear;
MarkNodePos(NodePos, step.type, step.from, step.to);
}
break;
}
}
}
for (int i = 0; i < n; i++) {
cout << "#" << (i + 1) << ":";
line[i].PrintList();
if (i != (n - 1))
cout << "\n";
}
return 0;
}
An example:
Input:
6 4
0 4 3
0 6 5
1 2 5
1 6 5
Output:
#1: 1
#2:
#3: 3 4
#4:
#5: 5 6 2
#6:
I keep getting wrong answer from the judge but as you can seen, I used a random number generator to test out my program and from my testing it all seems fine. I really have no clue what to look for. What could be causing the error?
I'm trying to create a program that gets string input from a text file, inserting the content into a list, word by word. I also have to calculate the numbers of the duplicates. My program works fine for the small input text file (1 line of string). But whenever I feed it with a bigger text file, it crashes. Any help will be great.
Here is my code:
#include <iostream>
#include <fstream>
#include <sstream>
using namespace std;
class Bag
{
private:
struct BagNode
{
string dataValue;
int dataCount;
BagNode *next;
BagNode(string);
};
BagNode *root;
string removePunctuations(string);
string toLower(string);
void insertData(string);
public:
Bag();
void procesFile(string, string);
void removeData(string);
void traverse();
};
Bag::BagNode::BagNode(string _data)
{
dataValue.assign(_data);
dataCount=1;
next = NULL;
}
Bag::Bag()
{
root = NULL;
}
void Bag::procesFile(string ifile, string ofile)
{
ifstream infile;
infile.open(ifile.c_str());
if (!infile.good())
{
cout<<"Input file not opening."<<endl;
return;
}
string line;
while(getline(infile,line))
{
stringstream lineStream(line);
string token = "";
while(lineStream >> token)
{
insertData(removePunctuations(token));
}
}
infile.close();
traverse();
cout<< endl <<"File processed successfully." << endl;
}
string Bag::removePunctuations(string data)
{
int length = data.size();
for(int i = 0; i < length; i++)
{
if(ispunct(data[i]))
{
data.erase(i--, 1);
length = data.size();
}
}
return data;
}
string Bag::toLower(string data)
{
for(int i = 0; data[i]; i++){
data[i] = tolower(data[i]);
}
return data;
}
void Bag::insertData(string data)
{
BagNode *n = new BagNode(data);
if (root == NULL)
{
root = n;
return;
}
BagNode *temp = root;
BagNode *prev = NULL;
string tdata;
data.assign(toLower(data));
while(temp != NULL)
{
tdata.assign(temp->dataValue);
tdata.assign(toLower(tdata));
if (tdata.compare(data) == 0)
{
temp->dataCount++;
return;
}
else
{
if (data.compare(tdata) < 0)
{
if (temp == root)
{
n->next = temp;
root = n;
return;
}
else
{
n->next = temp;
prev->next = n;
return;
}
}
}
prev = temp;
temp = temp->next;
}
n->next = temp;
prev->next = n;
}
void Bag::removeData(string data)
{
BagNode *temp = root;
BagNode *prev = NULL;
if (root->dataValue.compare(data)==0)
{
if (root->dataCount > 1)
root->dataCount--;
else
{
delete root;
root = NULL;
}
cout<<"Data removed successfully."<<endl;
return;
}
while (temp != NULL)
{
if (temp->dataValue.compare(data)==0)
{
if (temp->dataCount > 1)
temp->dataCount--;
else
{
prev->next = temp->next;
delete temp;
temp = NULL;
}
cout<<"Data removed successfully."<<endl;
return;
}
prev = temp;
temp = temp->next;
}
cout<<"Data not found match."<<endl;
}
void Bag::traverse()
{
if (root == NULL)
{
cout<<"No data."<<endl;
return;
}
BagNode *temp = root;
while(temp != NULL)
{
if (temp->dataCount > 1)
cout << temp -> dataValue << "(" << temp->dataCount << ")" << endl;
else
cout << temp -> dataValue << endl;
temp = temp->next;
}
}
int main(int argc, char *argv[])
{
bool outputConsole = false;
string infile, outfile = "\0";
cout << "Welcome!" << endl;
int option = -1;
do{
if (argc==1 || option == 1)
{
cout << "Enter the input file: ";
cin >> infile;
cout << "Enter the output file: ";
cin >> outfile;
}
else
{
infile.assign(argv[1]);
if (argc == 3)
outfile.assign(argv[2]);
}
Bag b;
b.procesFile(infile,outfile);
//b.traverse();
cout<<endl<<"If you want to input another file press 1 or 2 to quit: ";
cin>>option;
}while (option != 2);
return 0;
}
If ordering of words is not an issue,you should really try and use a hash table instead of a linked list as hash table is suitable for keeping track of duplicates.This will lead to O(1) insert operation (in ideal situation)
I am currently trying to learn C++ on my own and have been going through some textbooks and trying to do some problems. While learning pointers, I decided to try and implement a linked list on my own. I have written the program, but keep getting an error that says: "segmentation error (core dumped)". I have searched through other similar questions on this website and although there are a lot on the same topic, none have helped me fix my problem. I'm pretty new to programming and pointers, so any help will be appreciated!
#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;
struct node
{
int element;
struct node *next;
}*start;
class pointerlist
{
public:
node* CREATE(int num);
void ADD(int num);
int FIRST();
int END();
int RETRIEVE(int pos);
int LOCATE(int num);
int NEXT(int pos);
int PREVIOUS(int pos);
void INSERT(int pos, int num);
void DELETE(int pos);
void MAKENULL();
pointerlist()
{
start = NULL;
}
};
main()
{
pointerlist pl;
start = NULL;
pl.ADD(1);
cout << "Added 1" << endl;
for (int j=1; j<=5; j++)
pl.ADD(j);
cout << "The pointer implemented list is: " << endl;
for (int i=1; i<=5; i++)
{
cout << pl.END() << " " ;
}
cout << endl << endl;
}
void pointerlist::ADD(int num)
{
struct node *temp, *s;
temp = CREATE(num);
s = start;
while (s->next != NULL)
s = s->next;
temp->next = NULL;
s->next = temp;
}
node *pointerlist::CREATE(int num)
{
struct node *temp, *s;
temp = new(struct node);
temp->element = num;
temp->next = NULL;
return temp;
}
int pointerlist::FIRST ()
{
int num;
struct node *s;
s = start;
num = s->element;
return num;
}
int pointerlist::END()
{
struct node *s;
s = start;
int num;
while (s != NULL);
{
num = s->element;
s = s->next;
}
return num;
}
int pointerlist::RETRIEVE(int pos)
{
int counter = 0;
struct node *s;
s = start;
while (s != NULL)
{
counter++;
if (counter == pos)
{
return s->element;
}
s = s->next;
}
}
int pointerlist::LOCATE(int num)
{
int pos = 0;
bool flag = false;
struct node *s;
s = start;
while (s != NULL)
{
pos++;
if (s->element == num)
{
flag == true;
return pos;
}
s = s->next;
}
if (!flag)
return -1;
}
int pointerlist::NEXT(int pos)
{
int next;
int counter = 0;
struct node *s;
s = start;
while (s != NULL)
{
counter++;
if (counter == pos)
break;
s = s->next;
}
s = s->next;
next = s->element;
return next;
}
int pointerlist::PREVIOUS(int pos)
{
int previous;
int counter = 1;
struct node *s;
s = start;
while (s != NULL)
{
previous = s->element;
counter++;
if (counter = pos)
break;
s = s->next;
}
return previous;
}
void pointerlist::INSERT(int pos, int num)
{
struct node *temp, *s, *ptr;
temp = CREATE(num);
int i;
int counter = 0;
s = start;
while (s != NULL)
{
s = s->next;
counter++;
}
if (pos == 1)
{
if (start = NULL)
{
start = temp;
start->next = NULL;
}
else
{
ptr = start;
start = temp;
start->next = ptr;
}
}
else if(pos>1 && pos <= counter)
{
s = start;
for (i=1; i<pos; i++)
{
ptr = s;
s = s->next;
}
ptr->next = temp;
temp->next = s;
}
}
void pointerlist::DELETE(int pos)
{
int counter;
struct node *s, *ptr;
s = start;
if (pos == 1)
{
start = s->next;
}
else
{
while (s != NULL)
{
s = s->next;
counter++;
}
if (pos >0 && pos <= counter)
{
s = start;
for(int i=1; i<pos; i++)
{
ptr = s;
s = s->next;
}
ptr->next = s->next;
}
free(s);
}
}
void pointerlist::MAKENULL()
{
free(start);
}
The problem occurs in line 39 of my code (inside main where I write pl.ADD(1)). In this line I was trying to start off the list with the vale 1. There maybe be problems with the rest of my code too, but I have not been able to get past this line to check. Please help!
List is empty at the beginning, therefore it will fail on s-> next as s == start ==NULL :
s = start;
while (s->next != NULL)
Thanks for the help! I was able to fix the problem by adding a first function which adds the first element to the list. But now I am having trouble with my END function. It appears to not be entering the loop within the function when it is called. I cannot find a reason for this. Would anyone be able to help me figure out why my END function does not work?
I am writing a simple program for working with structure in C++. But there is a problem with memory. When my program calling a delete_element function it return memory's problem, but delete_all_list function working well. What I did wrong?
#include "iostream"
#include "string.h"
#include "limits" //ignore max
#include "stdlib.h" //atof
using namespace std;
struct Struct {
char text[10];
int age;
Struct *prev;
Struct *next;
};
int input(string msg) {
char str[2];
int check = 0, len = 0, var = 0, i = 0;
while (1){
cin.tellg();
cout<<msg;
cin.getline(str, 2);
if (cin.fail()) {
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(), '\n');
}
len = strlen(str);
check = 0;
for (i=0;i<len;i++) {
if(isdigit(str[i])) {
check++;
}
}
if (check==len && !(check==1 && str[0]=='-') && check != 0 && atoi(str) != 0){
var = atoi(str);
return var;
}
else {
cout<<"Error!"<<endl;
}
}
}
Struct* add_struct_to_list(Struct* prev){
Struct *NewStruct = 0;
char str[10];
int age;
cout<<"Name: ";
cin.getline(str, 10);
if (cin.fail()){
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(), '\n');
}
age = input("Age: ");
NewStruct = new Struct;
strcpy(NewStruct->text, str);
NewStruct->age = age;
NewStruct->prev= prev;
NewStruct->next= 0;
return NewStruct;
}
Struct* add_empty_struct_to_list(Struct* list_begin, int index){
int count = 1;
Struct* node = list_begin;
while (node->next) {
node = node->next;
count++;
}
while (count != index) {
Struct* NewStruct = new Struct;
strcpy(NewStruct->text, " ");
NewStruct->age = 0;
NewStruct->prev = node;
node->next = NewStruct;
NewStruct->next = NULL;
node = NewStruct;
count++;
}
return node;
}
void insert_struct_to_list(Struct* prev, Struct* next){
Struct *NewStruct = 0;
char str[10];
int age;
cout<<"Name: ";
cin.getline(str, 10);
if (cin.fail()){
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(), '\n');
}
age = input("Age: ");
NewStruct = new Struct;
strcpy(NewStruct->text, str);
NewStruct->age = age;
NewStruct->prev= prev;
NewStruct->next= next;
prev->next = NewStruct;
next->prev = NewStruct;
}
void replace_struct_in_list(Struct* ReStruct){
char str[10];
int age;
cout<<"Name: ";
cin.getline(str, 10);
if (cin.fail()){
cin.clear();
cin.ignore(numeric_limits<streamsize>::max(), '\n');
}
age = input("Age: ");
strcpy(ReStruct->text, str);
ReStruct->age = age;
}
Struct* start_new_list(int number) {
Struct* prevStruct = NULL;
Struct* newList = NULL;
for (int counter = 0; counter < number; counter++) {
Struct* newStruct = add_struct_to_list(prevStruct);
if (prevStruct)
prevStruct->next = newStruct;
if (counter == 0)
newList = newStruct;
prevStruct = newStruct;
}
return newList;
}
Struct* find_a_struct(Struct* list_begin, int index){
Struct* node = list_begin->next;
int count = 1;
if (node != NULL) {
while (node->next) {
node = node->next;
count++;
if (count == index) {
break;
}
}
if (count < index) {
node = NULL;
}
}
return node;
}
void add_extra_struct_to_list(Struct* list_begin) {
string command;
Struct* NewStruct = NULL;
int index = input("Enter index of new element (it should be less then 99): ");
Struct* FindedStruct = find_a_struct(list_begin, index);
if (FindedStruct != NULL) {
while (true) {
cout<<"This index is already exist. Replace? (Yes/No): ";
cin>>command;
cout<<endl;
if (command == "Yes" || command == "No") {
break;
}
}
if (command == "No") {
insert_struct_to_list(FindedStruct->prev, FindedStruct);
} else {
replace_struct_in_list(FindedStruct);
}
} else {
NewStruct = add_empty_struct_to_list(list_begin, index);
Struct* ExtraStruct = add_struct_to_list(NewStruct->prev);
NewStruct->next = ExtraStruct;
}
}
void delete_element(Struct* node) {
int index = 0; int count = 1;
bool is_index = false;
do {
index = input("Enter number of index: ");
} while (index <= 0);
do {
node = node->next;
count++;
if (count == index) {
Struct* prevs = 0;
prevs = node->prev;
Struct* nexts = 0;
nexts = node->next;
delete node;
prevs->next = nexts;
nexts->prev = prevs;
is_index = true;
break;
}
} while (node->next);
if (is_index == true) {
cout<<"Done!"<<endl;
} else {
cout<<"Index is out off range!"<<endl;
}
}
void delete_all_list(Struct* list_begin) {
Struct* structToDelete = NULL;
Struct* node = list_begin;
while (node->next) {
structToDelete = node;
node = node->next;
delete structToDelete;
}
delete node;
}
void sort_by_age(Struct* list_begin) {
Struct* node = 0;
Struct* node2 = 0;
int age; char text[10];
for (node = list_begin; node; node = node->next) {
for (node2 = list_begin; node2; node2 = node2->next) {
if (node->age < node2->age) {
strcpy(text, node->text);
strcpy(node->text, node2->text);
strcpy(node2->text, text);
age = node->age;
node->age = node2->age;
node2->age = age;
}
}
}
}
void print_list(Struct* list_begin) {
for (Struct* node = list_begin; node; node = node->next) {
cout<<"Age: "<<node->age<<"; Name: "<<node->text<<endl;
}
}
int main() {
int number;
Struct *NewList = 0;
string command;
bool list = false;
cout<<"\"help\" for more info"<<endl<<endl;
while (true) {
cout<<">>> ";
cin>>command;
cout<<endl;
if (command == "help") {
cout<<"startlist - creating a new double-linked list."<<endl;
cout<<"sortlist - sorting list by age of workers."<<endl;
cout<<"printlist - prining all list's elements."<<endl;
cout<<"addextra - adding extra element to list."<<endl;
cout<<"delete - delete element from list."<<endl;
cout<<"deletelist - delet all list. (Warning: require for create new list!)"<<endl;
cout<<"exit - close program."<<endl;
} else if (command == "startlist") {
if (list == false) {
number = input("Number of worker (it should be less than 99): ");
NewList = start_new_list(number);
cout<<"Done!"<<endl;
list = true;
} else {
cout<<"Error: You allready create one!"<<endl;
}
} else if (command == "sortlist"){
if (list == true) {
sort_by_age(NewList);
cout<<"Done!"<<endl;
} else {
cout<<"Error: You did't create a list or it is already sorted!"<<endl;
}
} else if (command == "printlist") {
if (list == true) {
print_list(NewList);
} else {
cout<<"Error: You did't create a list!"<<endl;
}
} else if (command == "delete") {
if (list == true) {
delete_element(NewList);
} else {
cout<<"Error: You did't create a list!"<<endl;
}
} else if (command == "deletelist") {
if (list == true) {
delete_all_list(NewList);
cout<<"Done!"<<endl;
list = false;
} else {
cout<<"Error: You did't create a list!"<<endl;
}
} else if (command == "addextra") {
if (list == true) {
add_extra_struct_to_list(NewList);
} else {
cout<<"Error: You did't create a list!"<<endl;
}
} else if (command == "exit") {
if (list == true) {
delete_all_list(NewList);
cout<<"Done!"<<endl;
}
break;
} else {
cout<<"Error: There is no such command!"<<endl;
}
cout<<endl;
}
return 0;
}
You have quite a few issues in your program, in the delete_element function your main problem is that you dereference prevs and nexts without checking whether they are NULL.
Adding some simple checks:
if (nexts && prevs)
prevs->next = nexts;
if (prevs && nexts)
nexts->prev = prevs;
Prevents it from segfaulting if any elements are NULL.
Other issues I have found I commented in the live example.
It looks suspicious that count starts from 1 instead 0 in delete_element. Because of this, the first index that your code is able to delete is 2 and you get into trouble if try to delete node 1.
EDIT: And one more thing: deleting the first node and last node needs some special care. For the first node, prev is 0 so you can not say prev->next.