Question

I’m building a app that need manage money datatype.

I’m new on Obj-c, so I can’t see the ligth in the use of NSDecimalNumber.

For example, in my unit test I do this:

@interface SamplePerson : NSObject {     NSString *name;     NSDate *birthDate;     NSInteger size;     NSNumber *phone;     NSDecimal balance;     BOOL *isOk; }  @property (nonatomic, retain) NSString *name; @property (nonatomic, retain) NSDate *birthDate; @property (nonatomic) NSInteger size; @property (nonatomic, retain) NSNumber *phone; @property (nonatomic) NSDecimal balance; @property (nonatomic) BOOL *isOk; --     o.balance = [NSDecimalNumber decimalNumberWithDecimal: [[NSNumber numberWithLong: 12.5] decimalValue]]; 

But get a warning:

warning: passing argument 1 of ‘save:’ from distinct Objective-C type

Overally, I dound this issue more complex than expected. I could hack using integers but I never do that in my 10+ years coding in Foxpro, Delphi, .NET, Python… never have issue for doing this kind of work.

Anyway, I wanna know how do this. I read the web but only found the same code as above and info like ‘Use NSDecimalNumber or get killed!’.

I wanna know how:

• Assing simple values, like 12.5
• Simple math
• How store & load from sqlite.

Thank you.

(btw: exist a library or utility that solve this? this sound like a common headache, rigth?)

Answer 1

The reason you’re getting that warning is because you declared balance as a primitive NSDecimal, instead of an NSDecimalNumber *. Take a look at this question as to why you should use NSDecimalNumber.