"EXC_BAD_ACCESS" in Qt - c++

Question

Basically, below is my main.cpp and when I try to run it with Qt's debugger, I get the "EXC_BAD_ACCESS" error ("Could not access memory") along with an arrow next to the first line of main (where it says Puzzle puzzle;). I thought it might be a problem with my Puzzle class, but when I moved that line elsewhere, I still got the bad access error with the debugger leaving the same yellow arrow by the first line of main. What's causing this error? My program ran fine half an hour ago, and then started throwing this error and I haven't even modified the code since it last worked. Also, this is one of my first projects in C/C++, so I'm not totally familiar with garbage collection. Could it be something to do with memory leaks or bad memory allocation?
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include "piece.h"
#include "puzzle.h"
#include "state.h"
using namespace std;
//function prototypes
Puzzle initPuzzle(string*, int);
int countWords(string);
//count the number of words (separated by white space) in a string
int countWords(string s){
int words = 0;
char * temp = new char[s.size() + 1];
copy(s.begin(), s.end(), temp);
temp[s.size()] = '\0';
temp = strtok (temp, " ");
while (temp != NULL){
words++;
temp = strtok (NULL, " ");
}
delete(temp);
return words;
}
//first checks validity of input
//if error(s), display appropriate message & exit program
//otherwise, returninstance of puzzle class from input file
//params: lines = array of strings, each of which is a line from input... size = # of elems in 'lines'
Puzzle initPuzzle(string * lines, int size){
//create instance of puzzle
//if bad piece found, throw it out
//if first piece (Z) is invalid, the next piece becomes goal piece
//if there are 0 valid pieces, display error to user and exit program
Puzzle ret;
int rows, cols;
if(size < 2){
//not enough lines for valid input
cout << "Error: Input too short" << endl << "Exiting program..." << endl;
exit(0);
}
istringstream iss(lines[0]);
if((iss >> rows >> cols) && countWords(lines[0])==2){
ret.rows=rows;
ret.cols=cols;
} else {
cout << "Error: Invalid first line" << endl << "Exiting program..." << endl;
exit(0);
}
if(rows < 1 || cols < 1){
cout << "Error: Invalid dimensions" << endl << "Exiting program..." << endl;
exit(0);
}
//now check the rest of the lines (ie the pieces)
for(int i=1; i<size; i++){
Piece newPiece;
int startRow, startCol, width, height;
char direction;
istringstream iss(lines[i]);
if(countWords(lines[i])==5 && (iss >> startRow >> startCol >> width >> height >> direction)){
//row is formatted correctly, create instance of Piece
newPiece = Piece(startRow, startCol, width, height, direction); //validate this piece later... if valid, add to pieces
} else {
//invalid row... entire input is invalid
cout << "Error: Invalid row(s)" << endl << "Exiting program..." << endl;
exit(0);
}
//now validate temporary piece...
//first make sure piece doesn't fall outside of grid
if(newPiece.startRow < 1 || newPiece.startCol < 1 || newPiece.startRow-1 > (rows - newPiece.height) ||
newPiece.startCol-1 > (cols - newPiece.width)){
//newPiece goes over the edge of the puzzle grid
cout << "Piece goes beyond grid... Throwing it out" << endl;
continue;
}
if(newPiece.direction != 'b' && newPiece.direction != 'h' && newPiece.direction != 'v' && newPiece.direction !='n'){
//newPiece has invalid direction
cout << "Piece has invalid direction... Throwing it out" << endl;
continue;
}
if(ret.pieceCount!=0 && ret.pieceOverlap(newPiece)){
//current piece overlaps existing one
cout << "Piece overlaps another piece... Throwing it out" << endl;
continue;
}
//if loop iteration reaches this point, piece is valid and can be added to puzzle
cout << "Piece is good!" << endl;
ret.addPiece(newPiece);
}
if(ret.pieceCount == 0){
//all pieces were invalid
cout << "Error: Puzzle has no pieces" << endl << "Exiting program..." << endl;
exit(0);
}
//now assign id's to the pieces...
for(int i=0; i<ret.pieceCount; i++){
if(i==0){
ret.pieces[i].id = 'Z';
} else {
ret.pieces[i].id = i;
}
}
return ret;
}
int main()
{
Puzzle puzzle; //single instance of puzzle class... initialized later after input & piece verification
string inputFile; //name of input file... provided by user
string line; //single line from input file
string * inputLines = new string[9000]; //array of lines from the input file
ifstream infile;
int size = -1; //size of inputLines array, initialized to -1
cout << "Enter name of input file: ";
cin >> inputFile;
infile.open(inputFile.c_str());
if(infile){
while(infile){
size++;
getline(infile,line);
inputLines[size] = line;
}
infile.close();
} else {
cout << "Error: Input file could not be opened" << endl << "Exiting program" << endl;
exit(0);
}
puzzle = initPuzzle(inputLines, size); //now check the input for validity, and if valid, initialize puzzle
return 0;
}

Answer 1

One mistake (two really) is within the function countWords():
temp is created using new[] but is deallocated use delete, it must be delete[] (new -> delete and new[] -> delete[] and avoid explicit dynamic memory management whenever possible)
the value of temp is not the value it was originally assigned which it must be when delete[]ing
Explicit dynamic memory allocation can be avoided completely by using a std::istringstream instead to count the words:
std::istringstream in(s);
std::string ignored;
while (in >> ignored) words++;
Other points:
prefer std::vector to explicit dynamic memory allocation management:
std::vector<std::string> inputLines; // and use 'push_back()'.
always check result of input operations immediately to ensure success:
if (cin >> inputFile)
{
ifstream infile(inputFile);
if (infile)
{
std::string line;
while (std::getline(infile, line)) lines.push_back(line);
}
}