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Hi I have a problem with my program, it opens a file correctly in the lineCounter function, counts and throws the number of lines in the file to the console, but then in the readFile function it grinds something and then throws the error below. It seems to me that the problem lies in dynamic memory allocation, because when I did the same thing in the main function with local variables everything worked fine.

Console output:

Console output

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

void lineCounter(string);
void readFile(string);
string encryption(string);
string decryption(string);

int howMuch;
int linesOfFile;
string buffer;
string pathToFile;
string *fileContent = new string[linesOfFile];

int main()
{
    cout << "If your file is in the program folder enter the name itself with the extension. If it is not, give the full path." << endl;
    cin >> pathToFile;
    cin.ignore();

    lineCounter(pathToFile);
    cout << linesOfFile;
    readFile(pathToFile);
    cout << *fileContent << endl;


    delete [] fileContent;
    fileContent = NULL;
    return 0;
}
void lineCounter(string pathToFile)
{
    fstream file;
    file.open(pathToFile, ios::in | ios::binary);
    if (file.is_open())
    {
        do
        {
            file >> buffer;
            linesOfFile++;

        }while(!file.eof());
        file.seekg(0);

        file.close();
        return;
    }
    else
        cout << "A critical error occurred" << endl;
    return;
}
void readFile(string pathToFile)
{
    fstream file;
    file.open(pathToFile, ios::in);
    if (file.is_open())
    {
        /*int i =0;
        do
        {
            file >> fileContent[i]; // tutaj jakis bląd
            i++;

        }while(!file.eof());*/

        for(int i = 0; i < linesOfFile; i++)
        {
            file >> buffer;
            fileContent[i] = buffer;
        }
        file.seekg(0);

        file.close();
        return;
    }
    else
        cout << "A critical error occurred" << endl;
    return;
}
string encryption(string word)
{
    int asciiProtection;

    for(int i = 0; i < word.length(); i++)
    {
        asciiProtection = word[i] + howMuch;

        if(asciiProtection < 65)
            word[i] += (26 + howMuch);
        else if(asciiProtection > 90)
            word[i] -= (26 - howMuch);
        else
            word[i] += howMuch;
    }

    return word;
}
string decryption(string word)
{
    int asciiProtection;

    for(int i = 0; i < word.length(); i++)
    {
        asciiProtection = word[i] - howMuch;

        if(asciiProtection < 65)
            word[i] += (26 - howMuch);
        else if(asciiProtection > 90)
            word[i] -= (26 + howMuch);
        else
            word[i] -= howMuch;
    }

    return word;
}
Adrian Mole
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SoSaymon
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1 Answers1

1

You allocate an array of size 0 here:

string *fileContent = new string[linesOfFile];

Reading lineOfFile afterwards from the user

cout << linesOfFile;

does not magically increase the size of the already allocated array. Any access to elements of that array, for example

fileContent[i] = buffer;

is out of bounds and causes undefined behavior.

TL;DR:

Use std::vector for dynamically sized arrays. It can resize when needed when you push_back more elements to it.

PS: There might be more issues in the code. One is while(!file.eof());. Why is iostream::eof inside a loop condition (i.e. `while (!stream.eof())`) considered wrong?. file.eof() as loop condition is wrong most of the time, because you need to read beyond the last entry before file.eof() returns true, hence your linesOfFile will be off by one.

463035818_is_not_an_ai
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