How do I print array of objects? Objective C

Question

I have the class Stockholging where its created the properties and methods costInDollars & valueInDollars.. I need to create a instance of each stock add each object to the array and then print it useing fast enumeration.

//Instantiation and creation of each stock

    StockHolding *o1 = [[StockHolding alloc]init];
    StockHolding *o2 = [[StockHolding alloc]init];
    StockHolding *o3 = [[StockHolding alloc]init];

//Setting the values, and calling the methods costInDollars and valueInDollars for each object

    [o1 setPurchaseSharePrice:2.30];
    [o1 setCurrentSharePrice:4.50];
    [o1 setNumberOfShares:40];
    [o1 costInDollars];
    [o1 valueInDollars];

    [o2 setPurchaseSharePrice:12.10];
    [o2 setCurrentSharePrice:10.58];
    [o2 setNumberOfShares:30];
    [o2 costInDollars];
    [o2 valueInDollars];

    [o3 setPurchaseSharePrice:45.10];
    [o3 setCurrentSharePrice:49.51];
    [o3 setNumberOfShares:210];
    [o3 costInDollars];
    [o3 valueInDollars];

// Creation an array and adding objects to the array

    NSMutableArray *bolsa = [[NSMutableArray alloc]init];
    [bolsa addObject:o1];
    [bolsa addObject:o2];
    [bolsa addObject:o3];

Please explain what you are expecting about printing? Debug or a report on paper? Also OSX or iOS? — zaph
– zaph, Commented Dec 31, 2013 at 13:03
Possible duplicate stackoverflow.com/questions/3396336/print-array-in-objective-c — Maheswaran Ravisankar
– Maheswaran Ravisankar, Commented Dec 31, 2013 at 13:08

FuzzyBunnySlippers · Accepted Answer · 2013-12-31 13:09:11Z

2

In your class, you need to provide a method for the description selector. This will return an NSString* of the contents of your class, formatted as you wish.

For example:

-(NSString*)description
{
   NSString* str1 = [NSString stringWithFormat:@"Purchase Share Price = %f",currentSharePrice];
   NSString* str2 = [NSString stringWithFormat:@"Current Share Price = %f",currentSharePrice];
   ... // do the rest of the items
   NSArray* strings =[NSArray arrayWithObjects:str1,str2,<the rest of them>, nil]
   NSString* result = [strings componentsJoinedByString:@"\n"];
   return result;
}

And then:

NSLog("%@",bolsa);

NOTE: This is a good approach whenever you need to debug/log objects in objective-c...having a method to convert complex objects into simple representations (i.e. a string) can be really helpful. Coding skill is not just knowing about functions and templates...its also about techniques and tools.

answered Dec 31, 2013 at 13:09

FuzzyBunnySlippers

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2 Comments

zaph Over a year ago

Actually it is good to add a description method to most classes.

FuzzyBunnySlippers Over a year ago

That is more of a developmental tradeoff...it takes time to add code...and somebody is (usually) writing the check for that time...if it is for a class used by others, it may get used and be valuable, but it may not. If you know it will be used, then it makes sense. A blanket "add this to all classes" can cost you a lot of time that you may have to use for other things...or defend when you are late. Balance is essential.

Grzegorz Krukowski · Accepted Answer · 2013-12-31 13:06:48Z

1

In your StockHolding class implement that method:

- (NSString*) description

Than use:

NSLog(@"%@", bolsa);

It will iterate through array and print string taken from above method for each object inside this array.

edited Dec 31, 2013 at 13:06

answered Dec 31, 2013 at 13:01

Grzegorz Krukowski

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