Can anyone explain the following code?
- (id)initWithTitle:(NSString*)title ratings:(float)rating;
(NSString*)title = first parameter , type =string, name = title
rating:(float)rating = ? ? ? What is the meaning of this ?
Float is a type and what is rating in start if the second rating is the name of parameter.
Objective-C methods are designed to be self documenting, and they borrow from the rich tradition of Smalltalk.
I'll try to explain what you have here, -(id)initWithTitle:(NSString*)title rating:(float)rating;
- (id)
This first portion indicates that this is an Objective C instance method that returns an id object. the - (dash) indicates that this is an instance method, where a + would indicate that this is a class method. The first value in parenthesis is the return value of the method.
initWithTitle:
This portion is a part of the message name. The full message name in this case is initWithTitle:rating:. The Objective-C runtime takes this method information and sends it to the indicated receiver. In pure C, this would look like
id initWithTitle(NSString* title, float rating). However, since this is Objective-C, additional information is packed into the message name.
(NSString*)title
This portion is part of the input. The input here is of type NSString* and has a local variable name of title.
rating:
This portion is the second part of the message name. As you can see here, message names are split up to help indicate what information you are passing to the receiver. Thus, if I were to message an object myObject with the variables foo and bar, I would type:
[myObject initWithTitle:foo rating:bar];
as opposed to C++ style:
myObject.initWithTitle(foo, bar);.
(float)rating
This is the last portion of the input. the input here is of type float and has a local variable name of rating.
Hopefully this is helpful!
This will guide you to have understanding about how to declare functions.
initWithTitle is a method name in objective-c,
title and rating are two parameter of initWithTitle method of type string and float respectively.
where ratings is just a name or identifier given to second part of parameter.
you can call this method using: [self initWithTitle:str ratings:0.5];
I hope your doubt is clear now :)
- (id)initWithTitle:(NSString*)title ratings:(float)rating;
in it you know that
(NSString*)title = first parameter , type =string, name = title
same way
ratings:(float)rating
ratings:is joined argument, type = float and rating is placeholder name in this function.
