That's the code:

#include <iostream>
#include <string.h>
using namespace std;
class List;

class Node{
    char data;

public:
    Node(char d):data(d),next(NULL){} // INICIALIZAÇÃO CONHECIDA COMO: inicialization list
    Node* next;
    char getData(){
        return data;
    }
    ~Node(){
        if(next!=NULL){
            delete next; // é tipo uma chamada recursiva, vai deletando tudo.
        }
    }
    friend class List;
};

class List{
    Node * head;
    Node * tail;

public:

    Node * begin(){
        return head;
    }
    List():head(NULL),tail(NULL){}
    void push_front(char  data){
        if(head == NULL){
            Node * n = new Node(data);
            head = tail = n;
        }
        else{
            Node * n = new Node(data);
            n->next = head;
            head = n;
        }
    }
    void push_back(char data){
        if(head==NULL){
            Node * n = new Node(data);
            head = tail = n;
        }else{
            Node * n = new Node(data);
            tail->next = n;
            tail = n;
        }
    }
    void insert(char data, int pos){
        if(pos==0){
            push_front(data);
            return;
        }
        Node* temp = head;
        for(int jump = 1; jump <=pos-1;jump  ){
            temp = temp->next;
        }
        Node *n = new Node(data);
        n->next = temp->next;
        temp->next = n;
    }

    ~List(){
        if(head!=NULL){
            delete head;
            head = NULL;
        }
    }
};

int main()
{

    List l;
    int i=0;
    char temp;
    char str[10000];
    int posx=0;

    while(scanf("%s", str) != '\0'){
        while(str[i] != '\0'){
                temp = str[i];
            if(str[i] == '['){
                while(str[i 1] != ']' && str[i 1] != '[' && str[i 1] != '\0'){

                    i  ;
                    temp = str[i];
                    l.insert(str[i], posx);
                    posx  ;
                }
            }else if(str[i] == ']'){
                while(str[i 1] != ']' && str[i 1] != '[' && str[i 1] != '\0'){
                    i  ;
                    l.push_back(str[i]);
                }
            }else{
                l.push_back(str[i]);
            }
            i  ;
            posx=0;
        Node *head = l.begin();
        while(head!=NULL){
            cout << head -> getData();
            head = head->next;
        }
        printf("\n");

        }


        i=0;
        l.~List();
    }

    return 0;
}

Being straight: The program gets a string, if the user types '[' the new characters (letters and underscores) will be added to the front, if the user inputs ']' then the cursor will move to the back.

The problem is: if I input [_text_[rinti]has[_the_]], before reaching has I have rinti_text_, and it's fine, but when it gets to has, the function push_back is called and it simply overwrites the word text, and after that I'll have rinti_has, instead of rinti_text_has. I do not know whats happening, but the problem seem to be with the function push_back. I would appreacite any hints or answers

CodePudding user response：

The bug is in your insert function. If you try to insert at the end of your List, you never update tail. A simple solution without modifying your code too much is to check if temp is equal to tail and just call push_back directly.

This code seems to work on my system.

    void insert(char data, int pos){
        if(pos==0){
            push_front(data);
            return;
        }
        Node* temp = head;
        for(int jump = 1; jump <=pos-1;jump  ){
            temp = temp->next;
        }
        if(temp == tail) {
            push_back(data);
        }
        else {
            Node *n = new Node(data);
            n->next = temp->next;
            temp->next = n;
        }
    }