Function Default value for argument in Objective-C

In Objective-C, we can provide default values for some or all arguments in a method or function. If no value is given for an argument, the default value will be used.

Here is an example of a method in Objective-C that uses a default value for an argument:

- (void)printGreetings:(NSString *)name timeOfDay:(NSString *)time {
  if (time == nil) {
    time = @"day";
  }
  NSLog(@"Good %@, %@", time, name);
}

In this method, the timeOfDay argument has a default value of nil. If no value is provided for timeOfDay, the default value of nil will be used.

So, when calling this method, we can either provide a value for timeOfDay or not:

// Providing a value for the timeOfDay argument
[self printGreetings:@"John" timeOfDay:@"morning"];
// Not providing a value for the timeOfDay argument and letting the default value of nil be used

[self printGreetings:@"Jane"];

In the first call to the method, the value of "morning" will be used for timeOfDay. In the second call, the default value of nil will be used for timeOfDay.

Therefore, using default values for arguments can make our code more flexible and easy to read, allowing us to provide reasonable default values for methods or functions when needed.