Fraction Calculator result keeps equaling zero

[benne199]

Ok so I keep getting this error in the debugging terminal and the problem is that whatever I write it keeps equaling 0, when I press the equals button.

GNU gdb 6.3.50-20050815 (Apple version gdb-1705) (Fri Jul  1 10:50:06 UTC 2011)
Copyright 2004 Free Software Foundation, Inc.
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This GDB was configured as "x86_64-apple-darwin".Attaching to process 12213.
Fraction_Calculator(12213,0xad2582c0) malloc: *** error for object 0x4b88f20: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug

myCalc is the only one released in the dealloc method so I don't get what it is trying to release

Here is the code please provide some pointers if you recognize the error, or else I guess I will just have to start from scratch and try to run through the whole code with the book again:

Thanks!

Code: (Objective-C)

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

@interface Fraction_CalculatorViewController : UIViewController {
    UILabel     *display;
    char        op;
    
    NSMutableString *displayString;
    int         currentNumber;
    BOOL        firstOperand, isNumerator;
    Calculator  *myCalc;
}

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

-(void) ProcessDigit: (int) digit;
-(void) ProcessOperator: (char) theOp;
-(void) storeFracPart;

// Numeric keys
 
-(IBAction) clickDigit: (id) sender;

// Operator keys

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

// Misc. keys

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

@end

Code: (Objective-C)

#import "Fraction_CalculatorViewController.h"

@implementation Fraction_CalculatorViewController

@synthesize displayString, display;

- (void)didReceiveMemoryWarning
{
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
    
    // Release any cached data, images, etc that aren't in use.
}

#pragma mark - View lifecycle

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    isNumerator = YES;
    firstOperand = YES;
    self.displayString = [NSMutableString stringWithCapacity: 40];
    myCalc = [[Calculator alloc] init];
    [super viewDidLoad];
}

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

// Numeric keys
-(IBAction) clickDigit: (id) sender
{
    int digit = [sender tag];
    
    [self ProcessDigit: digit];
}

-(void) ProcessOperator: (char) theOp
{
    NSString *opStr;
    
    op = theOp;
    
    switch (theOp) {
        case '+':
            opStr = @" + ";
            break;
        case '-':
            opStr = @" - ";
            break;
        case '*':
            opStr = @" × ";
            break;
        case '/':
            opStr = @" ÷ ";
            break;
    }
    
    [self storeFracPart];
    [displayString appendString: opStr];
    [display setText: displayString];
}

-(void) storeFracPart
{
    if (firstOperand) {
        if (isNumerator) {
            myCalc.operand1.numerator = currentNumber;
            myCalc.operand1.denominator = 1; // e.g 3 ÷ 4/5
        }
        else
            myCalc.operand1.denominator = currentNumber;
    }
    else if (isNumerator) {
        myCalc.operand2.numerator = currentNumber;
        myCalc.operand2.denominator = 1; // e.g 3 ÷ 4/5
        }
    else {
        myCalc.operand2.denominator = currentNumber;
        firstOperand = YES;
    }
    
    currentNumber = 0;
}

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

// Arithmetic operation keys

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

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

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

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

// Misc keys

-(IBAction) clickEquals: (id) sender
{
    [self storeFracPart];
    [myCalc performOperation: op];
    
    [displayString appendString: @" = "];
    [displayString appendString: [myCalc.accumulator convertToString]];
    [display setText: displayString];
    
    currentNumber = 0;
    isNumerator = YES;
    firstOperand = YES;
    [displayString setString: @""];
}

-(IBAction) clickClear: (id) sender
{
    currentNumber = 0;
    isNumerator = YES;
    firstOperand = YES;
    [myCalc clear];
    
    [displayString setString: @""];
    [display setText: displayString];
}


- (void)dealloc
{
    [myCalc release];
    [super dealloc];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

@end

[benne199]

I went through the entire code and it was all due to typos. Is debugging always this painful?

[skochan]