Question

Take the line

[angleLabelInRadians setText:[[NSString alloc] initWithFormat:@"%.3g", [poly angleInRadians]]]; 

When creating an NSString object within a message, do I still need to release this NSString and, if so, how would I do that, given that I haven’t created a pointer to the object?

Furthermore, is this correct coding procedure, or is this line too long? Would it be better to split it up in the following form?

NSString *polyRad = [[NSString alloc] initWithFormat:@"%.3g", [poly angleInRadians]];
[angleLabelInRadians setText:polyRad];
[polyRad release];

Answer 1

Unless you’re in an enviornment without an autorelease pool, you’ll most often just go with one of the convenience functions to do the above.

[angleLabelInRadians setText:[[NSString stringWithFormat:@"%.3g", [poly angleInRadians]]; 

If you do not want to use autoreleasing, you would have to do

NSString *s = [[NSString alloc] initWithFormat:@"%.3g", [poly angleInRadians]];
[angleLabelInRadians setText:s];
[s release];