如何在Xcode和Objective-C中正确调试

NSLog

NSLog(@"this text appears");

CGFloat pi = 3.14;
NSString *aFloatString = [NSString stringWithFormat:@"%.2f", pi];
NSLog(@"pi is equal to: %@", aFloatString);

%d %.2f %@ NSString*

#IFDEF

OUTPUT:
Number of vertices is: 1200
<Requested reduction>
Can I kick it?
....
....
YES. I. CAN!
Number of vertices is: 800

NSLog(@"Some status message here");
NSLog(@"The value of myObject is:%@", myObject);