Program 10.1

[th3ub3r3x]

In program 10.1

Code: (Objective-C)

#import "Fraction.h"
int main (int argc, char * argv[]) 
{
     @autoreleasepool {
          Fraction *a, *b;
          a = [[Fraction alloc] initWith: 1 over: 3];
          b = [[Fraction alloc] initWith: 3 over: 7];
          [a print]; [b print];

          [a release];
          [b release];
      }
return 0;
}

I don't understand the purpose of the final two statements (a and b release method invocations).  I typed the program in exactly how the book did and it gives me the error
'release' is unavailable: not available in automatic reference counting mode.

Thanks for the help
Mark Johnson

[dharr19]

Hi Mark,

The release statement isn't needed when using ARC.  Before Xcode 4.2, you had to manage memory taken up by objects.  When creating a new class look for the checkbox that says Use Automatic Reference Control. If you were to create program 10.1 again and uncheck that checkbox.  The program would work fine. The 10.1 program was from the previous edition and the release statements were just overlooked. If you remove them it will work fine.

Cheers
David