Thread: help with delete[]

Hi, can anyone help with this error "heap corruption detected" ?
Here is my program:

Code:

#include "stdafx.h"
#include "iostream"
#include "cassert"
using namespace std;

int capacity = 4; // default capacity
double* billsAndCoins = new double[capacity]; // data storage for change
int nBillsAndCoins = -1; // track the number of coins and bills
// -1 means invalid, 0 means no change due, >0 is #of bills+coins changed

bool set(double, double); // first parameter is price, last is amount paid
double calc(double, double); // first parameter is denomination, last is change
bool isValid(); // return false if the number of coins+bills 

int i; // iteration tracker
void myIterator(); // set index of array to 0
bool hasNext(); // return the index number of coins+bills in the array
double next(); // return a value from the array and advanced the index

void release(); // delete the dynamic allocated array

int main()
{
	set (14.57, 50);
	if (!isValid()) // function checks if #of bills+coins is 0 or greater
		cout << "Invalid input\n";
	else
	{
		// print the change
		for (myIterator(); hasNext();)
			cout << '[' << next() << ']';
	}
	cout << endl;

	set (63.68, 80);
	if (!isValid()) // function checks if #of bills+coins is 0 or greater
		cout << "Invalid input\n";
	else
	{
		// print the change
		for (myIterator(); hasNext();)
			cout << '[' << next() << ']';
	}
	cout << endl;

	release(); // contains the statement that deletes the dynamic array
	cin.get();
	return 0;
}

bool set(double price, double paid)
{
	double change = paid - price;
	if(change == 0)
	{
		nBillsAndCoins = 0;
		cout << "No Change";
		return true;
	}
	else if(change > 0)
	{
		nBillsAndCoins = 0;
		double money[11] = {100,50,20,10,5,1,0.5,0.25,0.1,0.05,0.01}; //denomination storage

		for(int j = 0; j < 11; j++)
			change = calc(money[j], change);

		// if the change is still not 0 due to some errors (the change become very small), it rounds off to 0
		if(change < 0.00001)
			change = 0;

		// if the change is still not 0 due to representational error, automatically allocate 1 penny to the array
		if(change >= 0.009)
		{
			change = 0;
			billsAndCoins[nBillsAndCoins] = 0.01;
			nBillsAndCoins++;
		}
		assert(change == 0);

		return true;
	}
	else
		return false;
}

double calc(double Money, double Change)
{
	while(Change >= Money)
	{
		// check and doubling the size y for overloading arrays
		if (nBillsAndCoins == capacity)
		{
			capacity *= 2;
			double* temp = new double[capacity];
			for (int i = 0; i < nBillsAndCoins; i++)
				temp[i] = billsAndCoins[i];
			delete [] billsAndCoins;
			billsAndCoins = temp;
		}

		Change -= Money;
		billsAndCoins[nBillsAndCoins] = Money;
		nBillsAndCoins++;
// but if I add " cout << Change << cin.get(); " the program has no error
	}
	return Change;
}

bool isValid()
{
	if(nBillsAndCoins < 0)
		return false;
	else
		return true;
}

void myIterator()
{
	i=0;
}

bool hasNext()
{
	return i >= 0 && i < nBillsAndCoins;
}

double next()
{
	return billsAndCoins[i++];
}

void release()
{
	delete [] billsAndCoins;
}

It would be much easier to debug if you used local variables instead and passed what is necessary as arguments to the functions.