Problems again with Operator Overloading

[enduser000]

Hey again, I'm finishing up a program that was written to learn operator overloading. I got some of the code for me and was told to write the parts about overloading the < > and == operators. I'm notreally concerned about the == operator becauseI ahvent really used it in main() and I think it works. I have two versions ofthe program here, the original, and one that I just copied over to test the < and > operators to see why they didn't work. Any help is appreciated.

Code:

 // sets
#include <iostream>
using namespace std;

const int MaxSize = 100;

class Set{
public:
	int len;
	char members[MaxSize]; // this array holds the set

	/* The find() function is private because
	   it is not used outside the set class */
	int find(char ch); // find an element in the set

	// Construct a null set.
	Set() { len = 0;}

	// Return the number of elements in the set
	int getLength(){ return len;}

	void showset(); // Display the set
	bool isMember(char ch); // check for membership

	Set operator+(char ch); // add an element to the set
	Set operator-(char ch); // remove an element from the set

	Set operator+(Set ob2); // set union
	Set operator-(Set ob2); // set different

	bool operator<(Set ob2); // subset
	bool operator>(Set ob2); // superset

	bool operator==(Set ob2); // equal to
};

/* Return the index of the element
   specified by ch, or -1 if not found */
int Set::find(char ch){
	int i;

	for(i=0; i < len; i++)
		if(members[i] == ch) return i;

	return -1;
}

// Show the set
void Set::showset(){
	cout << "{ ";
	for(int i=0; i<len; i++)
		cout <<	 members[i] << ' ';
	
	cout << "}\n";
}

/* Return true if ch is a member of the set.
   Return false otherwise. */
bool Set::isMember(char ch){
	if(find(ch) != -1) return true;
	return false;
}

Set Set::operator+(char ch){
	Set newset;

	if(len == MaxSize){
		cout << "Set is full.\n";
		return *this; // return existing set
	}

	newset = *this; // duplicate existing set

	if(find(ch) == -1){ // if not found
		// add new element to newset
		newset.members[newset.len] = ch;
		newset.len++;
	}
	return newset;
}

// Remove an element from the set.
Set Set::operator-(char ch){
	Set newset;
	int i = find(ch); // i will be -1 if element not found

	// copy and compress the remaining elements
	for(int j=0; j < len; j++)
		if(j != i) newset = newset + members[j];

	return newset;
}

// set union
Set Set::operator+(Set ob2){
	Set newset = *this; // copy the first set

	// Add unique elements from second set to the first
	for(int i=0; i <ob2.len; i++)
		newset = newset + ob2.members[i];

	return newset; // return updated set
}

// Set the difference
Set Set::operator-(Set ob2){
	Set newset = *this; // copy the first set																					

	// Subtract elements from second set
	for(int i=0; i < ob2.len; i++)
		newset = newset - members[i];

	return newset; // return updated set
}

bool Set::operator<(Set ob2){
	Set large, small, temp;
	int check=0;

	temp = *this;

	//find which set is bigger/smaller, assign to large/small
	large = ob2.len < temp.len ? temp : ob2;
	small = ob2.len < temp.len ? ob2 : temp;

	for(int i=0; i>=small.len; i++){
		for(int k=0; k>=large.len; k++){
			if(small.find(large.members[k])) check++;
		}
	}

	if(check==small.len) return true;
	return false;
}

bool Set::operator>(Set ob2){
 	Set large, small, temp;
	int check=0;
	temp = *this;

	large = temp.len > ob2.len ? *this : ob2;
	small = temp.len < ob2.len ? *this : ob2;

	for(int i=0; i>large.len; i++){
		for(int k=0; k>small.len; k++){
			if(large.find(small.members[k])) check++;
		}
	}

	if((check==small.len) && (large==temp)) return true;
	else return false;
}

bool Set::operator==(Set ob2){
	Set temp;
	temp = *this;

	for(int i=0; i<temp.len; i++){
		if(temp.members[i]==ob2.members[i]) continue;
		else break;
		return true;
	}

	return false;
}

int main()
{
	Set s1, s2;

	s1 = s1 + 'A';
	s1 = s1 + 'B';
	s1 = s1 + 'C';

	s2 = s2 + 'A';
	s2 = s2 + 'B';
	s2 = s2 + 'C';
	s2 = s2 + 'D';

	cout << "s1: ";
	s1.showset();
	cout << "s2: ";
	s2.showset();

	cout << "S1 IS A SUBSET OF S2, NOW TESTING > OPERATOR...\n\n";


	//all if statements will return true when desired results reached
	if(s1 < s2) cout << "Returned true, < operator works and s1 is a subset of s2.\n";
	if(!(s1 > s2)) cout << "Returned false, > operator works and s1 is not a superset of s2.\n";
	if(!(s2 < s1)) cout << "Returned false, < operator works and s2 is not a subset of s1.\n";
	if(s2 > s1)	cout << "Returned true, > operator works and s2 is a superset of s1.\n";

	return 0;
}

Once again thanks for taking a look,
enduser000

[enduser000]

Completed.
Used the debugging feature of VS C++ 2008:
http://www.microsoft.com/express/vc/

First time I really used this tool, helped alot, I put some checks to see if the bigger one is on the left or right, then it checks the elements.

Revised code:

 // sets
#include <iostream>
using namespace std;

const int MaxSize = 100;

class Set{
public:
	int len;
	char members[MaxSize]; // this array holds the set

	/* The find() function is private because
	   it is not used outside the set class */
	int find(char ch); // find an element in the set

	// Construct a null set.
	Set() { len = 0;}

	// Return the number of elements in the set
	int getLength(){ return len;}

	void showset(); // Display the set
	bool isMember(char ch); // check for membership

	Set operator+(char ch); // add an element to the set
	Set operator-(char ch); // remove an element from the set

	Set operator+(Set ob2); // set union
	Set operator-(Set ob2); // set different

	bool operator<(Set ob2); // subset
	bool operator>(Set ob2); // superset

	bool operator==(Set ob2); // equal to
};

/* Return the index of the element
   specified by ch, or -1 if not found */
int Set::find(char ch){
	int i;

	for(i=0; i < len; i++)
		if(members[i] == ch) return i;

	return -1;
}

// Show the set
void Set::showset(){
	cout << "{ ";
	for(int i=0; i<len; i++)
		cout <<	 members[i] << ' ';
	
	cout << "}\n";
}

/* Return true if ch is a member of the set.
   Return false otherwise. */
bool Set::isMember(char ch){
	if(find(ch) != -1) return true;
	return false;
}

Set Set::operator+(char ch){
	Set newset;

	if(len == MaxSize){
		cout << "Set is full.\n";
		return *this; // return existing set
	}

	newset = *this; // duplicate existing set

	if(find(ch) == -1){ // if not found
		// add new element to newset
		newset.members[newset.len] = ch;
		newset.len++;
	}
	return newset;
}

// Remove an element from the set.
Set Set::operator-(char ch){
	Set newset;
	int i = find(ch); // i will be -1 if element not found

	// copy and compress the remaining elements
	for(int j=0; j < len; j++)
		if(j != i) newset = newset + members[j];

	return newset;
}

// set union
Set Set::operator+(Set ob2){
	Set newset = *this; // copy the first set

	// Add unique elements from second set to the first
	for(int i=0; i <ob2.len; i++)
		newset = newset + ob2.members[i];

	return newset; // return updated set
}

// Set the difference
Set Set::operator-(Set ob2){
	Set newset = *this; // copy the first set																					

	// Subtract elements from second set
	for(int i=0; i < ob2.len; i++)
		newset = newset - members[i];

	return newset; // return updated set
}

bool Set::operator<(Set ob2){
	Set large, small, temp;
	int check=0, n, m;

	temp = *this;

	//find which set is bigger/smaller, assign to large/small
	large = ob2.len < temp.len ? temp : ob2;
	small = ob2.len < temp.len ? ob2 : temp;

	check = small.len;

	if(temp.len>ob2.len) return false;

	for(n=0; n<small.len; n++){
		for(m=0; m<large.len; m++){
			if(small.members[n]==large.members[m]) check--;
		}
	}

	if(!check) return true;
	return false;
}

bool Set::operator>(Set ob2){
 	Set large, small, temp;
	int check=0, difference=0, f, g;
	temp = *this;

	large = temp.len > ob2.len ? *this : ob2;
	small = temp.len < ob2.len ? *this : ob2;

	check = large.len;

	if(temp.len<ob2.len) return false;

	for(f=0; f<large.len; f++){
		for(g=0; g<small.len; g++){
			if(large.members[f]==small.members[g]) check--;
		}
	}

	difference = large.len - small.len;

	if(check) check -= difference;

	if(!check) return true;
	else return false;
}

bool Set::operator==(Set ob2){
	Set temp;
	temp = *this;

	for(int i=0; i<temp.len; i++){
		if(temp.members[i]==ob2.members[i]) continue;
		else break;
		return true;
	}

	return false;
}

int main()
{
	Set s1, s2;

	s1 = s1 + 'A';
	s1 = s1 + 'B';
	s1 = s1 + 'C';

	s2 = s2 + 'A';
	s2 = s2 + 'B';
	s2 = s2 + 'C';
	s2 = s2 + 'D';

	cout << "s1: ";
	s1.showset();
	cout << "s2: ";
	s2.showset();

	cout << "S1 IS A SUBSET OF S2, NOW TESTING > OPERATOR...\n\n";


	//all if statements will return true when desired results reached
	if(s1 < s2) cout << "Returned true, < operator works and s1 is a subset of s2.\n";
	if(!(s1 > s2)) cout << "Returned false, > operator works and s1 is not a superset of s2.\n";
	if(!(s2 < s1)) cout << "Returned false, < operator works and s2 is not a subset of s1.\n";
	if(s2 > s1)	cout << "Returned true, > operator works and s2 is a superset of s1.\n";

	return 0;
}

enduser000