Random floats

[Killbill]

Hi,
I'm trying to make an IBAction pick a random float from a fixed list (1.45, 3.89, 5.77 and 12.56).

In the viewDidLoad:

pickNumber = [[NSMutableArray alloc] init];
[pickNumber addObject:@"1.45"];
[pickNumber addObject:@"3.89"];
[pickNumber addObject:@"5.77"];
[pickNumber addObject:@"12.56"];

In the IBAction:
-(IBAction)butoonPressed: (id)sender{
result = [pickNumber objectAtIndexarc4random() % [pickNumber count])];

Obviously this isn't working, i get an error "Assigning to 'float' from incompatible type 'id'.
Any ideas how to get one of the numbers into "result"?

[RLScott]

Originally Posted by Killbill

Hi,
I'm trying to make an IBAction pick a random float from a fixed list (1.45, 3.89, 5.77 and 12.56).

In the viewDidLoad:

pickNumber = [[NSMutableArray alloc] init];
[pickNumber addObject:@"1.45"];
[pickNumber addObject:@"3.89"];
[pickNumber addObject:@"5.77"];
[pickNumber addObject:@"12.56"];

In the IBAction:
-(IBAction)butoonPressed: (id)sender{
result = [pickNumber objectAtIndexarc4random() % [pickNumber count])];

Obviously this isn't working, i get an error "Assigning to 'float' from incompatible type 'id'.
Any ideas how to get one of the numbers into "result"?

The objects you are adding to pickNumber are not floats or any other kind of numbers. They are strings. Look up the NSNumber class and how to use it.

[Killbill]

I am finding the documentation really difficult to apply...

[Duncan C]

Originally Posted by Killbill

I am finding the documentation really difficult to apply...

Look in the docs for NSNumber. Specifically, take a look at the methods numberWithFloat / numberWithDouble, and floatValue.

You could do this:

[myArray addObject: [NSNumber numberWithFloat: 10.3]];
[myArray addObject: [NSNumber numberWithFloat: 1.23]];
[myArray addObject: [NSNumber numberWithFloat: 2.47]];

Then, when you extract an object from the array, use code like this:

int randomIndex = arc4random()% [myArray count];
NSNumber* numberFromArray = [myArray objectAtIndex: randomIndex];
float value = [numberFromArray floatValue];

[crashmonkey]

It might be simpler to use a C array instead of objective C arrays and objects.
Then you don't have to mess with converting to NSNumber.

I usually use C arrays whenever I am dealing with primitive variables like ints and floats.