Question

I am writing simple program for solving crosswords. I am using getline to load crossword from input, but I am getting weird “Segmenation fault” messages and I really dont know what to do with it. Here is the code:

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


int** allocateCross(int rows, int columns)
{
    int ** cross = new int*[rows];
    for(int i=0;i<rows;i++)
    {
        cross[i] = new int[columns];    
    }
    return cross;
}
void changeValue(int **cross, int rowPosition, int columnPosition, int value)
{
    cross[rowPosition][columnPosition] = value;
}
void printCross(int ** cross, int rows, int columns)
{
    for(int i=0;i<rows;i++){
        for(int j=0;j<columns;j++){
            cout << cross[i][j];
        }
        cout << endl;
    }

}
void setCross(int ** cross, int rows,int columns, int spaces[], int numberOfSpaces)
{
        for(int i=0;i<6;i++){
        for(int j=0;j<6;j++){
            changeValue(cross, i, j, 0);

        }
        for(int i=0;i<(numberOfSpaces*2);i=i+2)
        {
            changeValue(cross, spaces[i], spaces[i+1],1);
        }

    }
}
int testString(string stringToTest, const string allowedChars)
{
    size_t found = stringToTest.find_first_not_of(allowedChars);
    if(found != string::npos)
        return false;
    else
        return true;
}

void wrongInput()
{
    cout << "Wrong input." << endl;
    exit(0);
}
int main()
{
    string line;
    string top;
    string line_r;
    bool stringTester;
    int columns = 0;
    int rows = 0;
    getline(cin,line);
    if(line!="Enter crossword:")
        wrongInput();
    getline(cin,line);
    stringTester = testString(line,"+-");
    if(stringTester != true)
        wrongInput();
    top = line;
    top.erase(top.begin());
    top.erase(top.begin()+(top.size()-1));
    rows = top.size();
    top = line;
    getline(cin,line);
    while(line != top)
    {
        columns++;
        getline(cin,line);
    }


    int ** cross = allocateCross(rows,columns);
    //int spaces[]={};
    setCross(cross,rows,columns,spaces,0);
    printCross(cross,rows,columns);


    return 0;
}

The only important part is the while cycle. When i enter this input:

Enter crossword:
+----+
|  * |
|    |
| *  |
+----+

Everything is fine until i enter the second +—-+ where the script shoud stop, then i get segmenation fault. Can someone help me please?

Answer 1

First of all, read the comments written.

The problem seems here:

for(int i=0;i<6;i++){
    for(int j=0;j<6;j++){
        changeValue(cross, i, j, 0);
    }
}

Why this value (6) is hardcoded? Why 6 and not 42? You crossword in the example has three lines and four columns (3×4), but the cycle goes through 6×6 matrix.