Objective-C Note

Hello World

#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
@autoreleasepool {
NSLog(@"Hello World!");
}
return 0;
}

Comments

// single line comment
/*
Multi-lines
comment
*/

Variables

#import <Foundation/Foundation.h>
#define My_constant_var 31337
int main(int argc, const char * argv[]) {
@autoreleasepool {
int my_var = 42;
NSLog(@"%d",my_var);
NSLog(@"%d",My_constant_var);
}
return 0;
}

Shorthand assignment

a += b # a = a + b
a -= b # a = a - b
a *= b # a = a * b
a /= b # a = a / b
a %= b # a = a % b
a **= b # a = a**b

Input

#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
@autoreleasepool {
NSFileHandle *inputHandle = [NSFileHandle fileHandleWithStandardInput];
NSData *data = [NSData dataWithData:[inputHandle availableData]];
NSString *input = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

NSLog(@"%@", input);
}
return 0;
}

Array

#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
@autoreleasepool {
NSArray *peoples = @[@"Alice", @"Bob", @"Eve"];
NSLog(@"%@", peoples[0]);   // Output: Alice
NSLog(@"%@", peoples[1]);   // Output: Bob
NSLog(@"%@", peoples[2]);   // Output: Eve

NSMutableArray *foo = [NSMutableArray arrayWithObjects:@42, @"Cindy", @0.02, @YES, nil];
[foo addObject:@"d"];
[foo addObject:@1337];
[foo insertObject:@0.05 atIndex:2];

[foo removeLastObject];
[foo removeObjectAtIndex:2];

NSLog(@"%@", foo);
NSLog(@"%@", foo);

NSArray *alph = @[@"a", @"c", @"z", @"e"];
NSLog(@"%@", [alph subarrayWithRange:NSMakeRange(1, 3)]);
NSArray *x = @[@41, @53];
NSArray *y = @[@72, @16, @133];
NSArray *res = [x arrayByAddingObjectsFromArray:y];
res = [y arrayByAddingObjectsFromArray:x];
NSArray *z = @[@16, @41, @55];

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"NOT SELF IN %@", z];
res = [res filteredArrayUsingPredicate:predicate];

NSLog(@"%@", res);
}
return 0;
}