Chapter13~26:OC Basic - <Objective-C Programming>

#include vs. #import

A message send

class methods vs. instance methods

A message with an argument

a message send with three arguments

alloc and init

sending message to nil

memory management

how to declare instance variable and instance methods

#import <> vs. #import ""

using custom classes

setter and getter

setter and getter naming conventions

using properties replace instance variables

#import <Foundation/Foundation.h>
#import "BNRPerson.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // create an intance of BNRPerson
        BNRPerson *mikey = [[BNRPerson alloc]init];
        // give the instance variables interesting values using setters
        [mikey setHeightInMeters:1.8];
        [mikey setWeightInKilos:96];
        
        // log the instance variables using the getters
        float mikeyHeight = [mikey heightInMeters];
        int mikeyWeight = [mikey weightInKilos];
        NSLog(@"mikey is %.2f meters tall and weighs %d kilograms", mikeyHeight, mikeyWeight);
        

        // log some values using custom methods;
        float mikeyBMI = [mikey bodyMassIndex];
        NSLog(@"mikey has a BMI of %f", mikeyBMI);

        
    }
    return 0;
}

dot notation

Another attribute that you will see shortly is copy. Practically speaking, whenever you declare a property that points to an NSString or an NSArray, you should include the copy attribute