Objective-C Basics

Question 1

Interpolate Most Basic

Answer 1

(@”%@”, @”Ari”);

Question 2

Interpolate Most Basic Print To Command Line

Answer 2

NSLog(@”%@”, @”Ari”);

Question 3

primatives

Answer 3

NSInteger
NSUInteger
CGFloat
BOOL

Question 4

primitives vs objects

Answer 4

objects hold values and can change them through behaviors called “methods”, while primitives just hold a value.

Question 5

NSUInteger

Answer 5

An integer value that can only be zero or positive (the “U” means “unsigned”).
0,1,2,3,4

Question 6

NSInteger Format Specifier

Answer 6

%li

Question 7

NSUInteger Format Specifier

Answer 7

%lu

Question 8

CGFloat Format Specifier

Answer 8

%f or %.nf, where n is the number of decimal places to display

Question 9

BOOL Format Specifier

Answer 9

%d

Question 10

Help -> Documentation and API Reference

Answer 10

⇧⌘0

Question 11

what is “calling a method”

Answer 11

its simply using a method [object method]

Question 12

standard method call syntax

Answer 12

ReturnType *captureVariable = [recipientObject methodNameArgument:argumentVariable];

Question 13

multiple method call syntax example

Answer 13

NSString *shorthandWelcome = [welcome stringByReplacingOccurrencesOfString:stringToReplace withString:replacementString];

Question 14

has prefix has suffix example

Answer 14

NSString *lafayette =
@”Marquis Marie-Joseph Paul Yves Roch Gilbert du Motier de Lafayette”;

BOOL isMarquis = [lafayette hasPrefix:@”Marquis”];
BOOL isLafayette = [lafayette hasSuffix:@”Lafayette”];

if (isMarquis && isLafayette) {
NSLog(@”Ladies and gentlemen, the Marquis de Lafayette”);
}

Question 15

stringByAppendingString Example

Answer 15

NSString *welcome = @”Welcome to “;
welcome = [welcome stringByAppendingString:@”the Flatiron School!”];

NSLog(@”%@”, welcome);