What is the purpose of the @interface and @implementation directives?

Vaibhav Kothia May 26, 2023 0 Comments

The @interface and @implementation directives are used to define a class in Objective-C.

@interface defines the class interface, which includes the class name, the superclass it inherits from, and any methods, properties, and instance variables the class has.

@implementation defines the class implementation, which includes the actual code for the methods, properties, and instance variables declared in the interface.

Example:

@interface MyClass : NSObject

@property (nonatomic, strong) NSString *name;

– (void)sayHello;

@end

@implementation MyClass

@synthesize name;

– (void)sayHello {
NSLog(@”Hello %@”, self.name);
}

@end

What is the difference between a class and an object?

Vaibhav Kothia May 26, 2023 0 Comments

Class: A class is a blueprint for creating objects. It is a template that describes the properties and behaviors of a type of object.

For example, a class called “Car” could describe the properties of a car, such as its color, make, model, and year. It could also describe the behaviors of a car, such as accelerating, braking, and turning.

Object: An object is an instance of a class. It is a concrete example of the class, with its own set of data and behaviors.

For example, a car object could be a specific car, such as a red Honda Accord from 2019. This object would have its own color, make, model, and year, and it would be able to accelerate, brake, and turn.