Question

i have a problem.
When i compile my program there isn’t a error but, when i start it these retern with “EXC_BAD_ACCESS”.
I looking for the error with the debug and i find it in these method but i don’t understand where…

PS:the program enters in the loop sometimes.

-(void)updateMinPosition{

    float valueMinX = 150;
    float valueMinY = 150;
    float valueMinZ = 150;

    NSString *nameMinimoX = [NSString   stringWithFormat:@"default"];
    NSString *nameMinimoY = [NSString   stringWithFormat:@"default"];
    NSString *nameMinimoZ = [NSString   stringWithFormat:@"default"];

    for(int i = 0; i< [arrayPosizioniMovimento count]; i++){

        //Posizione is my class. It contain a NSString name, 3 float valueX, valueY, valueZ
        Posizione *tempPosition;
        tempPosition = [[Posizione alloc]init];

        tempPosition = [arrayPosizioniMovimento objectAtIndex:i];

        if(tempPosition.valueX <= valueMinX){
            valueMinX = tempPosition.valueX;
            nameMinimoX = tempPosition.nome;
        }

        if(tempPosition.valueY <= valueMinY){
            valueMinY = tempPosition.valueY;
            nameMinimoY = tempPosition.nome;
        }

        if(tempPosition.valueZ <= valueMinZ){
            valueMinZ = tempPosition.valueZ;
            nameMinimoZ = tempPosition.nome;
        }

        [tempPosition dealloc];
    }

    labelMinX.text = nameMinimoX;
    labelMinY.text = nameMinimoY;
    labelMinZ.text = nameMinimoZ;   
}

Answer 1

For the 1st glance there’re several problems with your code:

    Posizione *tempPosition;
    tempPosition = [[Posizione alloc]init];

    tempPosition = [arrayPosizioniMovimento objectAtIndex:i];

Here in the second line you create new Posizione instance and right after that assign another value to the same variable. In effect that will mean that your created instance will be never used and cause memory leak. To use element from array just write

Posizione *tempPosition = [arrayPosizioniMovimento objectAtIndex:i];

The second one – is the following line

[tempPosition dealloc];

First of all you should never call this method directly but rather send an object -release message – it will be deallocated automatically when its retain count becomes 0. In your case you do not retain tempPosition object in that code so there;s no need to release it here – just remove that line.

P.S. Using fast enumeration can also make your code more readable and less error prone:

for (Posizione *tempPosition in arrayPosizioniMovimento){
   if(tempPosition.valueX <= valueMinX){
...