debugging and runtime errors

[ironman]

I have been working on this program for awhile and have had a lot of runtime errors in it. i have gotten most of the bugs out of it but still find values that cause the program to crash. can some one please help find some?

#ifndef DMEMORY_H
#define DMEMORY_H

class Dmemory
{
friend void copy(Dmemory *destination, const Dmemory *source);
public:
	Dmemory(int size = 100);
	~Dmemory();
	bool setSize(int newSize);
	int getSize() const;
	int getValue(int index) const;
	bool setValue(int index, int value);
	void freeMemory();
private:
	int *ptr; // pointer to dynamically allocated array
	int size; // current size of the array
};
#endif

//#include "Dmemory.h"
#include <iostream>
using namespace std;

Dmemory::Dmemory(int s)
{
	size = s;
	ptr = NULL;
	cout << "[***PTR***] New Dmemory Object, ptr: " << ptr
		<< "; size: " << size << endl;
}

Dmemory::~Dmemory()
{
	cout << "[***PTR***] Destroying object, ptr: " << ptr << endl;
}

bool Dmemory::setSize(int newSize)
{
	ptr = new int[newSize];
	size = newSize;
	cout << "[***PTR***] Resize Dmemory Object, ptr: " << ptr <<
		"; size: " << size << endl;
	if(ptr == 0)
		return false; // could not allocate
	else
		return true;
}

int Dmemory::getSize() const
{
	return size;
}

int Dmemory::getValue(int index) const
{
	return ptr[index];
}

bool Dmemory::setValue(int index, int value)
{
	ptr[index] = value;
	return true;
}

void Dmemory::freeMemory()
{
	delete [] ptr;
}

void copy(Dmemory *destination, const Dmemory *source)
{
	*destination = *source;
	cout << "[***PTR***] After copy destination ptr: " << destination->ptr
		<< " and source ptr: " << source->ptr << endl;
}


//#include "Dmemory.h"
#include <iostream>
using namespace std;

// function to set all values of a Dmemory object to "value"
void setMemory(Dmemory &x, int value);
// function to verify integrity of Dmemory object
// assumes that all values have been set to "value"
void checkMemory(const Dmemory &x, int value);

int main()
{
	int size, index, fillValue, experiment;
	int value1, value2;
	int i,count;
	Dmemory object3(0);
	
	while(true) {
		cout << "type experiment type (1-6, 0 to stop): ";
		cin >> experiment;
		if (experiment == 0) break;
		Dmemory object1; // allocate objects each time through the loop
		Dmemory object2;
	
		switch (experiment) {
		case 1: 
			cout << "index: ";
			cin >> index;
			cout << "value: ";
			cin >> fillValue;
			cout << "value at " << index << " is " << object1.getValue(index) << endl;
			object1.setValue(index,fillValue);
			cout << "value at " << index << " is " << object1.getValue(index) << endl;
			break;
		case 2: 
			cout << "size: ";
			cin >> size;
			if(!object1.setSize(size)) {
				cout << "******** out of space";
				return (1);
			}
			cout << "Object resized" << endl;
			cout << "index:";
			cin >> index;
			cout << "value: ";
			cin >> fillValue;
			cout << "(Before calling setValue) value at " << index << " is " << object1.getValue(index) << endl;
			object1.setValue(index,fillValue);
			cout << "(After calling setValue) value at " << index << " is " << object1.getValue(index) << endl;
			break;
		case 3:
			cout << "size: ";
			cin >> size;
			if(!object1.setSize(size)) {
				cout << " out of space";
				return (1);
			}
			if(!object2.setSize(size)) {
				cout << "******** out of space";
				return (1);
			}
			cout << "value: ";
			cin >> value1;
			setMemory(object1, value1);
			value2 = value1+10;
			setMemory(object2, value2);
			cout << "Set value of index which is out of range: ";
			cin >> i;
			object2.setValue(i,value2);
			checkMemory(object1,value1);
			break;
		case 4:
			cout << "size: ";
			cin >> size;
			if(!object1.setSize(size)) {
				cout << " out of space";
				return (1);
			}
			if(!object2.setSize(size)) {
				cout << "******** out of space";
				return (1);
			}
			cout << "index:";
			cin >> index;
			cout << "value: ";
			cin >> fillValue;
			object1.setValue(index,fillValue);
			fillValue = fillValue+10;
			object2.setValue(index,fillValue);
			cout << "(object1) value at " << index << 
				" is " << object1.getValue(index) << endl;
			cout << "(object2) value at " << index << 
				" is " << object2.getValue(index) << endl;
			copy(&object2, &object1);
			cout << "after copy\n";
			cout << "(object1) value at " << index << 
				" is " << object1.getValue(index) << endl;
			cout << "(object2) value at " << index << 
				" is " << object2.getValue(index) << endl;
			fillValue = fillValue+10;
			object2.setValue(index,fillValue);
			cout << "after changing object 2\n";
			cout << "(object1) value at " << index << 
				" is " << object1.getValue(index) << endl;
			cout << "(object2) value at " << index << 
				" is " << object2.getValue(index) << endl;
			break;
		case 5:
			cout << "size: ";
			cin >> size;
			cout << "index:";
			cin >> index;
			cout << "starting value: ";
			cin >> fillValue;
			cout << "count: ";
			cin >> count;
			for(i = 0; i < count; i++) {
				if(!object1.setSize(size)) {
					cout << "****** out of space\n";
					return (1);
				}
				object1.setValue(index,fillValue++);
				cout << "(object1) value at " << index <<
					" is " << object1.getValue(index) << endl;
			}
			break;
		case 6:
			cout << "size: ";
			cin >> size;
			if(!object1.setSize(size)) {
				cout << "****** out of space\n";
				return (1);
			}
			cout << "index: ";
			cin >> index;
			cout << "initial value: ";
			cin >> fillValue;
			object1.setValue(index, fillValue++);
			object1.freeMemory();
			if(!object3.setSize(size)) {
				cout << "****** out of space\n";
				return (1);
			}
			object3.setValue(index, fillValue);
			cout << "(object3) value at " << index << 
				" is " << object3.getValue(index) << endl;
			object1.setValue(index,fillValue + 1000);
			cout << "after setting object1 at " << index << " to " << fillValue + 1000 << endl;
			cout << "(object3) value at " << index << 
				" is " << object3.getValue(index) << endl;
			break;
		default:
			cout << "******* bad experiment number, reenter:";
		}
	}
	return 0;
}

// function to set all values of a Dmemory object to "value"
void setMemory(Dmemory &x, int value)
{
	for(int i = 0; i < x.getSize(); i++) {
		x.setValue(i,value);
	}
}
// function to verify integrity of Dmemory object
// assumes that all values have been set to "value"
void checkMemory(const Dmemory &x, int value)
{
	for(int i=0; i < x.getSize(); i++) {
		if(x.getValue(i) != value) {
			cout << "corrupted value in object at " << i 
				<< " value is " << x.getValue(i) 
				<< " but should be value " << value << endl;
		}
	}
}

[Zaita]

We aren't here to test your code =\

However. By merely looking at just the DMemory class I found these issues:
1) Your constructor takes a size arguement, but doesn't allocate any space for ptr
2) Your destructor doesn't free ptr if it's been allocated.
3) setSize() doesn't check if ptr has already been allocated. It should de-allocate already allocated memory
4) getValue and setValue do not check if index is valid.
5) freememory doesn't check if memory has been allocated first before trying to clear
6) copy doesn't free the memory stored by destination. It also isn't doing a true copy but merely moving a pointer.
7) none of your DMemory class has any exception handling to track runtime errors.