Need assistance with Segmentation Error - c++

Question

The following code is giving me the following error
Error description :
Unhandled exception at 0x00DC5D81 in ImageComponent2.exe: 0xC0000005: Access violation reading location 0xCDCDCDD5.
// ImageComponents
#include <iostream>
#include "Position.h"
using namespace std;
void labelComponents(int size, int **pixel);
void outputImage(int size, int **pixel);
int main(){
int size = 0;
cout << "Enter image size: ";
cin >> size;
int ** pixel = new int *[size + 2];
for (int i = 1; i <= size; i++)
{
pixel[i] = new int[size + 2];
}
cout << "Enter the pixel array in row-major order:\n";
for (int i = 1; i <= size; i++)
for (int j = 1; j <= size; j++)
{
cin >> pixel[i][j];
}
labelComponents(size, pixel);
outputImage(size, pixel);
system("pause");
return (0);
}
void labelComponents(int size, int **pixel){
// initialize offsets
Position * offset = new Position[4];
offset[0] = Position(0, 1); // right
offset[1] = Position(1, 0); // down
offset[2] = Position(0, -1); // left
offset[3] = Position(-1, 0); // up
int numNbr = 4; // neighbors of a pixel position
Position * nbr = new Position(0, 0);
Position * Q = new Position[size * size];
int id = 1; // component id
int x = 0; // (Position Q)
// scan all pixels labeling components
for (int r = 1; r <= size; r++) // row r of image
for (int c = 1; c <= size; c++) // column c of image
{
if (pixel[r][c] == 1)
{// new component
pixel[r][c] = ++id; // get next id
Position * here = new Position(r, c);
do
{// find rest of component
for (int i = 0; i < numNbr; i++)
{// check all neighbors of here
nbr->setRow(here->getRow() + offset[i].getRow());
nbr->setCol(here->getCol() + offset[i].getCol());
if (pixel[nbr->getRow()][nbr->getCol()] == 1)
{// pixel is part of current component
pixel[nbr->getRow()][nbr->getCol()] = id;
Q[x] = *nbr;
x++;
}
}
// any unexplored pixels in component?
*here = Q[x]; // a component pixel
x--;
} while (here != NULL);
} // end of if, for c, and for r
}
} // end of labelComponents
void outputImage(int size, int **pixel){
cout << "The labeled image is: ";
for (int i = 1; i <= size; i++){
cout << endl;
for (int j = 1; j <= size; j++)
cout << pixel[i][j] << " ";
}
} // end of outputImage
//Position.h
#ifndef POSITION_H
#define POSITION_H
class Position
{
private:
int row; // row number of the position
int col;
// column number of the position
public:
Position(); // default
Position( int theRow, int theCol); // parameter
Position(const Position & aPosition); // copy
Position & operator = (const Position & aPosition); // overload =
// overload =
// mutators
void setRow (int r);
void setCol (int c);
//accessors
int getRow() const;
int getCol() const;
}; // end Position
Position::Position()
{
setRow(0);
setCol(0);
}
Position::Position(int r, int c)
{
setRow(r);
setCol(c);
}
Position::Position(const Position & aPosition)
{
setRow(aPosition.row);
setCol(aPosition.col);
}
Position & Position::operator=(const Position & aPosition)
{
this->row=aPosition.row;
this->col=aPosition.col;
return(*this);
}
void Position::setRow(int r)
{
this->row = r;
}
void Position::setCol(int c)
{
this->col = c;
}
int Position::getRow() const
{
return this->row;
}
int Position::getCol() const
{
return this->col;
}
#endif

Answer 1

In C/C++, arraw indexes go from 0 to n-1, not from 1 to n. All your for loops are wrong:
for (int i = 1; i <= size; i++)
Must be replaced by:
for (int i = 0; i < size; i++)
Else, you access array at sizeposition which is out of bound.
Using a debugger and/or working with smaller piece of code would have made it easier for you to figure this out ;-)