How do I pass multiple parameters in Objective-C

Question

I have read several of the post about Objective-C method syntax but I guess I don t understand multiple names for a method   I m trying to create a method called getBusStops with NSString and NSTimeInterval parameters and a return type of NSMutableArray  This is how I have constructed the method but it obviously gets errors at runtime   -  NSMutableArray   getBusStops  NSString   busStop                                  NSTimeInterval   timeInterval    I saw another example with a method   - NSInteger pickerView  UIPickerView   pickerView             numberOfRowsInComponent  NSInteger component   I don t understand why this method has a method name for each parameter  Should I do the same with something like   -  NSMutableArray   getBusStops  NSString   busStop                         forTime  NSTimeInterval   timeInterval

User · Answer

int  add   int  numberOne plus   int  numberTwo    returnType  functionPrimaryName    returnTypeOfArgumentOne  argumentName functionSecondaryNa   me     returnTypeOfSecontArgument  secondArgumentName     as in other languages we use following syntax void add int one  int second  but way of assigning arguments in OBJ c is different as described above

User · Answer

for create method     - void mymethods  NSString   aCont withsecond  NSString   a-second     method definition        for call the method       mymethods self contoCorrente withsecond self asecond

User · Answer

Yes  the Objective-C method syntax is like this for a couple of reasons  one of these is so that it is clear what the parameters you are specifying are  For example  if you are adding an object to an NSMutableArray at a certain index  you would do it using the method   -  void insertObject  id anObject atIndex  NSUInteger index    This method is called insertObject atIndex  and it is clear that an object is being inserted at a specified index   In practice  adding a string  Hello  World   at index 5 of an NSMutableArray called array would be called as follows   NSString  obj     Hello  World    int index   5    array insertObject obj atIndex index     This also reduces ambiguity between the order of the method parameters  ensuring that you pass the object parameter first  then the index parameter  This becomes more useful when using functions that take a large number of arguments  and reduces error in passing the arguments   Furthermore  the method naming convention is such because Objective-C doesn t support overloading  however  if you want to write a method that does the same job  but takes different data-types  this can be accomplished  take  for instance  the NSNumber class  this has several object creation methods  including       id numberWithBool  BOOL value     id numberWithFloat  float value     id numberWithDouble  double value    In a language such as C    you would simply overload the number method to allow different data types to be passed as the argument  however  in Objective-C  this syntax allows several different variants of the same function to be implemented  by changing the name of the method for each variant of the function

User · Answer

Objective-C doesn t have named parameters  so everything on the left side of a colon is part of the method name  For example   getBusStops  forTime    is the name of the method  The name is broken up so it can be more descriptive  You could simply name your method  getBusStops      but that doesn t tell you much about the second parameter

User · Answer

The text before each parameter is part of the method name   From your example  the name of the method is actually  -getBusStops forTime    Each   represents an argument   In a method call  the method name is split at the  s and arguments appear after the  s  e g    getBusStops  arg1 forTime  arg2

User · Answer

You need to delimit each parameter name with a     at the very least  Technically the name is optional  but it is recommended for readability  So you could write   -  NSMutableArray  getBusStops  NSString  busStop   NSSTimeInterval  timeInterval    or what you suggested   -  NSMutableArray  getBusStops  NSString  busStop forTime  NSSTimeInterval  timeInterval

[objective-c] How do I pass multiple parameters in Objective-C?

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