Fraction Calculator on iPhone problem :-(

[lolipop]

So, while making the fraction calculator from the book, I did the exact code in the book, and did everything correctly. And so it worked.
So thats nice, so I tweaked it. And then it didn't work.
There are no errors, but I am keep getting the answer as 0 when I try to use it. What did I do wrong?
What I tweaked it is I made it so you can enter as many fractions you want at once, rather then only two. I made an array, put the fractions in there, and for calculating I enumerated and added (or whatever) them. Its lots of code, but please help!

Fraction Class

Code: (Objective-C)

#import <UIKit/UIKit.h>



@interface Fraction : NSObject <NSCopying>
{
	int numerator;
	int denominator;
	
}

@property int numerator, denominator;

- (void) print;
- (void) setTo: (int) n over: (int) d;
- (double) convertToNum;
- (NSString *) convertToString;
- (void) reduce;

- (Fraction*) add: (Fraction *) f;
- (Fraction*) subtract: (Fraction *) f;
- (Fraction*) multiply: (Fraction *) f;
- (Fraction*) divide: (Fraction *) f;


@end

Code: (Objective-C)

#import "Fraction.h"


@implementation Fraction

@synthesize numerator, denominator;

- (void) print
{
	NSLog (@"%i/%i", numerator, denominator);
}

- (double) convertToNum
{
	if (denominator != 0)
		return (double) numerator / denominator;
	else
		return 1.0;
}

- (NSString *) convertToString {
	if (numerator == 0) 
		return @"0";
	if (numerator == denominator) {
			return @"1";
	}
	else if ( denominator ==  1)
		return [NSString stringWithFormat: @"%i", numerator];
	else
		return [NSString stringWithFormat: @"%i/%i", numerator, denominator];
}

- (void) setTo: (int) n over: (int) d
{
	numerator = n;
	denominator = d;
	
}



- (void) reduce
{
	int u = numerator;
	int v = denominator;
	int temp;
	
	while (v != 0) {
		temp = u % v;
		u = v;
		v = temp;
	}
	
	numerator /= u;
	denominator /= u;
}


- (Fraction*) add: (Fraction *) f
{
	// To add two fractions:
	// a/b + c/d = ((a*d) + (b*c)) / (b * d)
	
	Fraction *result = [[Fraction alloc] init];
	int resultNum, resultDenom;
	
	resultNum = (numerator * f.denominator) + (denominator * f.numerator);
	resultDenom = denominator * f.denominator;
	
	[result setTo: resultNum over: resultDenom];
	
	[result reduce];
	return [result autorelease];
}

- (Fraction*) subtract: (Fraction *) f
{
	// To subtract two fractions:
	// a/b - c/d = ((a*d) - (b*c)) / (b * d)
	
	Fraction *result = [[Fraction alloc] init];
	int resultNum, resultDenom;
	
	resultNum = (numerator * f.denominator) - (denominator * f.numerator);
	resultDenom = denominator * f.denominator;
	
	[result setTo: resultNum over: resultDenom];
	
	[result reduce];
	return [result autorelease];
}

- (Fraction*) divide: (Fraction *) f
{
	
	Fraction *result = [[Fraction alloc] init];
	int resultNum, resultDenom;
	
	resultNum = (numerator * f.denominator);
	resultDenom = denominator * f.numerator;
	
	[result setTo: resultNum over: resultDenom];
	
	[result reduce];
	return [result autorelease];
}

- (Fraction*) multiply: (Fraction *) f
{
	
	Fraction *result = [[Fraction alloc] init];
	int resultNum, resultDenom;
	
	resultNum = (numerator * f.numerator);
	resultDenom = denominator * f.denominator;
	
	[result setTo: resultNum over: resultDenom];
	
	[result reduce];
	return [result autorelease];
}
- (id) copyWithZone: (NSZone *) zone
{
	Fraction *newFraction = [[Fraction allocWithZone: zone] init];
	
	newFraction.numerator = self.numerator;
	newFraction.denominator = self.denominator;
	
	return [newFraction autorelease];
}


@end

View Controller

Code: (Objective-C)

#import <UIKit/UIKit.h>
#import "Calculator.h"

@interface Fraction_CalculatorViewController : UIViewController 
{
	UILabel         *display;
	char             op;
	int              currentNumber;
	NSMutableString *displayString;
	BOOL             isNumerator;
	Calculator      *myCalculator;


}
@property (nonatomic, retain) IBOutlet UILabel *display;
@property (nonatomic, retain) NSMutableString *displayString;

-(void) processDigit: (int) digit;
-(void) processOp: (char) theOp;
-(void) storeFracPart;

// Numeric keys

-(IBAction) clickDigit: (id) sender;

//Arithmetic Operation keys

-(IBAction) clickPlus: (id) sender;
-(IBAction) clickMinus: (id) sender;
-(IBAction) clickMultiply: (id) sender;
-(IBAction) clickDivide: (id) sender;

// Misc. Keys

-(IBAction) clickOver: (id) sender;
-(IBAction) clickEquals: (id) sender;
-(IBAction) clickClear: (id) sender;

@end

Code: (Objective-C)

#import "Fraction_CalculatorViewController.h"

@implementation Fraction_CalculatorViewController

@synthesize display, displayString;


- (void)viewDidLoad {
	isNumerator = YES;
	self.displayString = [NSMutableString stringWithCapacity: 40];
	myCalculator = [[Calculator alloc] init];
    [super viewDidLoad];
}

-(void) processDigit: (int) digit
{
	currentNumber = currentNumber * 10 + digit;
	[displayString appendString: [NSString stringWithFormat: @"%i", digit]];
	[display setText: displayString];
}

-(IBAction) clickDigit: (id) sender
{
	int digit = [sender tag];
	
	[self processDigit: digit];
}

-(void) processOp: (char) theOp
{
	NSString *opStr;
	op = theOp;
	
	switch (theOp) {
		case '+':
			opStr = @" + ";
			break;
		case '-':
			opStr = @" - ";
			break;
		case '*':
			opStr = @" * ";
			break;
		case '/':
			opStr = @" / ";
			break;
	}
	
	
	[self storeFracPart];
	isNumerator = YES;
	[myCalculator.fractions addObject: [myCalculator.operand copy]];
	[myCalculator.operand setTo: 0 over: 1];
	
	[displayString appendString: opStr];
	[display setText: displayString];
}

-(void) storeFracPart
{
	if (isNumerator) {
		myCalculator.operand.numerator = currentNumber;
		myCalculator.operand.denominator = 1; // e.g. 3 * 4/5


	}
	else {
		myCalculator.operand.denominator = currentNumber;


	}
	currentNumber = 0 ;
}

-(IBAction) clickOver: (id) sender
{
	[self storeFracPart];
	isNumerator = NO;
	[displayString appendString: @"/"];
	[display setText: displayString];
}

// Arithmetic Operation keys

-(IBAction) clickPlus: (id) sender
{
	[self processOp: '+'];
}

-(IBAction) clickMinus: (id) sender
{
	[self processOp: '-'];
}

-(IBAction) clickMultiply: (id) sender
{
	[self processOp: '*'];
}

-(IBAction) clickDivide: (id) sender
{
	[self processOp: '/'];
}

// Misc. Keys

-(IBAction) clickEquals: (id) sender
{

		
	[self storeFracPart];
	


	[myCalculator performOperation: op];
	
	[displayString appendString: @" = "];
	[displayString appendString: [myCalculator.accumulator convertToString]];
	[display setText: displayString];
	
	currentNumber = 0;
	isNumerator = YES;
	[displayString setString: @""];


		

}
			
-(IBAction) clickClear: (id) sender
{
	isNumerator = YES;

	currentNumber = 0;
	[myCalculator clear];
	
	[displayString setString: @""];
	[display setText: displayString];
}

- (void) dealloc
{
	[myCalculator dealloc];
	[super dealloc];
}

@end

Calculator Class

Code: (Objective-C)

#import <UIKit/UIKit.h>
#import "Fraction.h"

@interface Calculator : NSObject 
{
	Fraction *accumulator;
	Fraction *operand;
		NSMutableArray  *fractions;

}

@property (retain, nonatomic) Fraction *operand, *accumulator;
@property (retain, nonatomic) NSMutableArray *fractions;

- (void) performOperation: (char) op;
- (void) clear;

@end

Code: (Objective-C)

#import "Calculator.h"


@implementation Calculator
@synthesize operand, accumulator, fractions;

- (id) init
{
	self = [super init];
	
	operand = [[Fraction alloc] init];
	accumulator = [[Fraction alloc] init];
				   
	return self;
}

- (void) clear
{
	if (accumulator) {
		accumulator.numerator = 0;
		accumulator.denominator = 0;
	}
}

- (void) performOperation: (char) op
{
	Fraction *nextFrac;
	[accumulator setTo: 0 over: 1];
	switch (op) {
			
		case '+':
			
			for (nextFrac in fractions) {
				accumulator = [accumulator add: nextFrac];
			}
			break;
		case '-':
			for (nextFrac in fractions) {
				accumulator = [accumulator subtract: nextFrac];
			}
			break;
		case '*':
			for (nextFrac in fractions) {
				accumulator = [accumulator multiply: nextFrac];
			}
			break;
		case '/':
			for (nextFrac in fractions) {
				accumulator = [accumulator divide: nextFrac];
			}
			break;
	}
	
	

}



		
-(void) dealloc
{
	[operand release];
	[accumulator release];
	[super dealloc];
}
@end

[skochan]

You're never allocating your fractions array.  I didn't look any further than that, as that's a show stopper.  Look at the init method in the Calculator class.  Don't forget to release it in dealloc if you use alloc to create it.

Cheers,

Steve Kochan

[lolipop]

Wow, I can't believe I missed that! Thanks for bothering to read over the code :-D