This is my school program that crashes on me, probably something from (Segmentation fault / Bus error / Memory limit exceeded / Stack limit exceeded). I can't figure out where the mistake is. I tried to comment on the code and reduce it a bit.

Retrieving information from the file in the form [name] [surname] [number]

Martin Jeff 123456789

Tomas Adam 234567890

This is followed by a blank line [\ n]

And then I search by the entered name, surname or both

Martin

Thomas

Adam

Martin Jeff

...

Thank you in advance for your advice.

class Uzivatel
{
    public:
        string name;
        string surname;
        string number;
};

void alocation(int &velPole, Uzivatel *arr)
{
    velPole = 2*velPole;
    Uzivatel *tmp = new Uzivatel[velPole];
    arr = tmp;
    delete []tmp;
}


void getString(const string & fileName, ostream &strStream)
{
    ifstream ifs;
    ifs.open(fileName);
    
    if(ifs.is_open())
    {
        strStream << ifs.rdbuf();
        ifs.close();
    }
}

void finding(int pocet, Uzivatel *uzivatele, ostream &out, string &line)
{
    string name = "";  string surname = ""; string number = "";
    int matches = 0;

    stringstream s(line);
    s >> name >> surname >> number;

    if(!(surname.compare("")))
      surname = name;
              
    for(int i=0; i<pocet; i  )
    {
        if( (!name.compare(uzivatele[i].name)) || (!surname.compare(uzivatele[i].surname)) )
          {
            out << uzivatele[i].name << " " << uzivatele[i].surname << " " << uzivatele[i].number << endl;
            matches   ;
          }
    }
    out << "-> " << matches <<endl;
}

bool isValid(string &jmeno, string &prijmeni, string &cislo)
{
  int x = cislo.find_first_not_of("0123456789");
  int y = cislo.length(); 
  
  if((!x) || cislo[0] == '0' || y != 9 || jmeno=="" || prijmeni=="" || cislo=="" )
    return false;

  return true;
}

bool report ( const string & fileName, ostream & out )
{
    
    ifstream ifs;
    stringstream strStream;
    getString(fileName, strStream);

    int arrLen = 200;
    Uzivatel *uzivatele = new Uzivatel[arrLen];
    int arrElem = 0;

    string line;
    bool hledani = false;

    while (getline(strStream, line))
    {
        if(hledani)
        { 
            finding(arrElem, uzivatele, out, line);   
        }
        else
        {
            stringstream s(line);

            string konec = "";
            s >> uzivatele[arrElem].name >> uzivatele[arrElem].surname >> uzivatele[arrElem].number >> konec;

            /* If there was anything else at the entrance*/
            if(konec!="")
            {
              delete []uzivatele;
              return false;
            }
            
            /* Realloc */
            if(arrElem == arrLen)
              alocation(arrLen, uzivatele);
                      
            arrElem  ;

            /* Enter'\n' */
            if(!line.compare(""))
                {
                    hledani = true;
                    arrElem--;

                    /* Validation enter */
                    for(int i=0; i<arrElem;i  )
                    {
                        if(!(isValid(uzivatele[i].name, uzivatele[i].surname, uzivatele[i].number)))
                        {
                          delete []uzivatele;
                          return false;
                        }
                    }
                }
        }

    }
    if(!hledani)
    {
      delete []uzivatele;
      return false;
    }
    delete []uzivatele;
    return true;
}

int main ()
{
  ostringstream oss;
  oss . str ( "" );
  assert ( report( "tests/test0_in.txt", oss ) == true );
  assert ( oss . str () ==
    "John Christescu 258452362\n"
    "John Harmson 861647702\n"
    "-> 2\n"
    "-> 0\n"
    "Josh Dakhov 264112084\n"
    "Dakhov Speechley 865216101\n"
    "-> 2\n"
    "John Harmson 861647702\n"
    "-> 1\n" );
  oss . str ( "" );
  assert ( report( "tests/test1_in.txt", oss ) == false );

  return 0;
}

Test0 (Work correct):

John    Christescu  258452362
Peter   Herreran    716973426
Josh    Dakhov  264112084
John    Harmson 861647702
Dakhov  Speechley   865216101

John
Martin
Dakhov
Harmson

CodePudding user response：

You code as posted with the input data you gave (those 2 lines) works, except that the second assert fails. The reason being that you never write to the out stream in 'report'.

The reason it fails with a larger data set is due to this function

void alocation(int& velPole, Uzivatel* arr)
{
    velPole = 2 * velPole;
    Uzivatel* tmp = new Uzivatel[velPole];
    arr = tmp;
    delete[]tmp;
}

This function does nothing. It allocates a new larger array of Uzi objects, then deletes it. I assume its actually trying to delete the old one thats too small

You should return the new pointer after deleting the old one.

Much better would be std::vector which will do this all for you

Also why read the whole file into memory as a stringstream then read the stringstream, why not use the file stream directly?