objective c appending string cocos2d - string

Question

Hello I am writing an application and I want to create a string.
so I use that
NSString *scoreString;
NSString *cupCakesPassedString;
NSString *cupCakes;
int cupCakesPassed;
int totalCupCakesPerLevel;
-(void)spriteMoveFinished:(id)sender {
CCSprite *sprite = (CCSprite *)sender;
[self removeChild:sprite cleanup:YES];
if (sprite.position.y <= 0) {
sprite.position = ccp( sprite.position.x,768 );
score+=5;
scoreString=[NSString stringWithFormat:#"%i",score];
[label setString:scoreString];
cupCakesPassed++;
cupCakesPassedString=[NSString stringWithFormat:#"%i",cupCakesPassed];
cupCakes=[[cupCakesPassedString stringByAppendingString:#"/"]stringByAppendingString:totalCupCakes];
[passingCupCakes setString:cupCakes];
}
}
it crashes!! but if use another string like scoreString it works...
in init method I have
totalCupCakesPerLevel=30;
scoreString=[NSString stringWithFormat:#"%i",score];
cupCakesPassedString=[NSString stringWithFormat:#"%i",cupCakesPassed];
totalCupCakes = [NSString stringWithFormat:#"%i",7];
cupCakes=[[cupCakesPassedString stringByAppendingString:#"/"]stringByAppendingString:totalCupCakes];
if I do this
cupCakes=[[cupCakesPassedString stringByAppendingString:#"/"]stringByAppendingString:scoreString];
I also has in init method that
cupCakes=[[cupCakesPassedString stringByAppendingString:#"/"]stringByAppendingString:totalCupCakes];
and actually works...until the method is called.
the numbers might be wrong but are for testing purposes
it seems that the problem is with string totalCupCakes,since even if I use #"test" works but what is wrong with that string?

Answer 1

Using a string method like this:
cupcakes = [NSString stringWithFormat:#"%d/%d", cupCakesPassed, totalCupCakes];
Would be simpler to use instead of the appending strings.

Answer 2

If I understand right, all your problems are because of non-retained strings. All stringWith... constructors of NSString class returns autoreleased objects. Retain them after creation and release in your dealloc method.
In your case to the moment of calling method, strings are deallocated and are not valid objects