Swift Tutorial for Beginners

import Foundation

// The content of the greeting
var message = "Hello every body"

// sayHello() function
func sayHello()  {
    
    // Call print function to print out a message
    // Note that you can not call this function in the Top-Level.
    print(message)
    
}

import Foundation


print("Hello, World!")

// Call sayHello() function.
// Defined in MyFirstSwift.swift
sayHello()

// Declare a variable.
var <Variable name> : <Data Type> ;

// Declares a variable, and assign a value to it.
var <Variable name> : <Data Type> = <value>;

// Declare a constant:
let <Constant name> : <Data Type> = <value>;

// Example
// Declare a variable
// Name of variable: year
// Data type: Int
// Value: 2016
var year: Int = 2016;

// With primitive data types (Int, Double, Bool) and String, 
// you can ignore in the declaration.
// Swift can understand your intentions.
..

// Inferred as String
var languageName = "Swift"     
var version = 1.0  // Double
var introduced = 2014  // Int
var isAwesome = true   // Bool

import Foundation

// Use the keyword 'let' to declare a constant.
// Constant name is COPYRIGHT, data type is String.
// And its value is "o7planning".
// (This is a constant declared in Top-Level
// It can be used in other source files in the project).
let COPYRIGH: String = "o7planning"

// Use the keyword 'var' to declare a variable.
// Name of variable: year
// Data type: Int
// Value: 2016
// (This is a variable declared in Top-Level
// It can be used in other source files in the project).
var year: Int = 2016 

func variableExample()  { 
    // Declare a constant integer.
    // You can not assign new values for the constants.
    let MAX_SCORE = 100;
    
    // Declare an integer variable.
    var score = 90;
    
    // Declare a string
    var studentName = "Tom"
    
    // Write string to the Console.
    print("Hi \(studentName)") 
    print("Your score: \(score)/\(MAX_SCORE)") 
    print("Assign new value for studentName")
    
    // Assign new value for studentName.
    studentName = "Jerry"
    print("Hi \(studentName)")  
}

import Foundation

// Call variableExample() function, 
// is defined in VariableExample.swift file.
variableExample()

if ( condition )  {
    // Do something here.
}

// Example 1:
if ( 5 < 10 )   {
   print( "Five is now less than ten");
} 
// Example 2:
if ( true )   {
    print( "Do something here");
}

// Note that at most one block of code will be executed.
// The program checks the conditions from top to bottom.
// When a condition is true, this block will be executed.
// The remaining conditions will be ignored.
...

// If condition1 is true then ..
if (condition1 )  
{
     // Do something if condition1 is true.
}
// Else if condition2 is true then ....
else if(condition2 )  
{
    // Do something here if condition2 is true (condition1 is false).
}
// Else if conditionN is true then ...
else if(conditionN )  
{
     // Do something if conditionN is true 
     // (All the above conditions are false)
}
// Else (All the above conditions are false).
else  {
     //  Do something.
}

import Foundation 

func  ifElseExample()  { 
    // Declare a variable type of UInt32 with random value.
    // (arc4random() function return random value).
    var randomValue: UInt32 = arc4random() 
    print("Random value = " + String(randomValue))
    
    // Division 200 and returns the remainder
    // (Return 0 -> 99)
    var age: UInt32 = randomValue % 200; 
    print("Your age= " + String(age))
    
    // Check if age < 80 then
    if (age < 80)    {
        print("You are pretty young");
    } 
    // Else if age between 80 and 100 then
    // Ngược lại nếu age nằm giữa 80 và 100 thì ..
    else if  age >= 80 && age <= 100     {
        print("You are old");
    } 
    // Else (The remaining cases).
    else    {
        print("You are very old");
    } 
}

import Foundation

func switchExample1()   { 
    // Require users to select an option.
    print("Please select one option:") 
    print("1 - Play a game")
    print("2 - Play music")
    print("3 - Shutdown computer")
    print("---------------------")
    
    // Declare a variable type of UInt32 with random value.
    // (arc4random() function return random value).
    // Khai báo một biến kiểu UInt32 với giá trị ngẫu nhiên.
    // (Hàm arc4random() trả về một số ngẫu nhiên).
    var randomValue: UInt32 = arc4random()
    
    // Division 5 and returns the remainder (0, 1, 2, 3, 4)
    var myValue:UInt32 = randomValue%5
    
    // Declare a variable 'option'.
    // Cast UInt32 to Int.
    // 'option' value in 1, 2, 3, 4, 5.
    var option:Int = Int(myValue) + 1
    
    // String(option): Cast data type to String.
    print("You select: " + String(option))
    
    // Check the value of 'option'.
    switch (option)   { 
    case 1:
        print("You choose to play the game");
    case 2:
        print("You choose to play the music");
    case 3:
        print("You choose to shutdown the computer");
    // Others case.
    default:
        print("Nothing to do...");
    } 
}

import Foundation 

func switchExample2() { 
    // Declare a varable and assign value of 3.
    var option = 3 
    print("Option = \(option) ")
    
    // Check value of 'option'.
    switch (option)    { 
    case 1:
        print("Case 1") 
    // Case value in 2,3,4,5
    case 2, 3, 4, 5:
        print("Case 2,3,4,5!!!") 
    // Case value in 6 -> 10
    case 6...10:
        print("Case 6...10") 
    // Case value in 11 -> 20 and odd.
    case 11...20 where option % 2 == 1:
        print("Case 11...20 and odd") 
    default:
        print("Nothing to do...") 
    }  
}

import Foundation

func switchFallthroughExample()  {  
    var option = 15  
    switch (option)   { 
    case 0...10:
        print("Case 0...10")
        // fallthrough: Execute next case.
        fallthrough 
    case 11...20:
        print("Case 11...20")
        // fallthrough: Execute next case.
        fallthrough 
    case 21...30:
        print("Case 21...30")
        // fallthrough: Execute next case.
        fallthrough 
    case 31...40:
        print("Case 31...40") 
    case 41...50:
        print("Case 41...50") 
    default:
        print("Default case")
    } 
}

for <element> in <collection> {
       // Do something here..
}

import Foundation 

func forInExample1()  { 
    // Declare an array type of String with 5 elements.
    var languages:[String] = ["Java","C#", "C/C++", "Swift", "Ruby"]  
    for lang in languages  { 
        print("Language " + lang)
    } 
}

for (initialize variable ; condition ; updates new value for variable )
{
        // Execute the block when the condition is true
}

// Example 1:
// Declare a variable x and assign value 0.
// The condition is x < 5
// If x < 5 is true then execute the block.
// After each iteration, the value of x is increased by 1.
for (int  x = 0;  x < 5 ; x = x + 1)
{
    // Do something here when x < 5 is true.
}  
// Example 2:
// Declare variable x and assgin value of 2
// The condition is x < 15
// If x < 15 is true then execute the block.
// After each iteration, the value of x is increased by 3.
for (int  x = 2;  x < 15 ; x = x + 3)
{
    // Do something here when x < 15 is true.
}

import Foundation 

func forLoopExample()   { 
    print("For loop example"); 
    // Declare variable x and assign value of 2
    // The condition is x < 15
    // If x < 15 is true then execute the block.
    // After each iteration, the value of x is increased by 3
    for (var x = 2; x < 15; x = x + 3)    {
        print( );
        print("Value of x = \(x)");
    } 
}

while (condition)  
{
     // While the 'condition' is true, then execute the block.
}

// Declare a variable x.
int x = 2;

while ( x < 10)
{
    // Do something here when x < 10 is true.
    ...
    	
    // Update value to x.
    x = x + 3;
}

import Foundation

func whileLoopExample()   { 
    print("While loop example"); 
    // Declare a variable x and assign value of 2
    var x = 2; 
    // The condition is x < 10.
    // If x < 10 is true then execute the block.
    while (x < 10)  { 
        print("Value of x = \(x)"); 
        x = x + 3;
    } 
}

// Characteristics of the 'repeat-while' loop is that it will  execute the block at least 1 time.
// Once finished block, it will check  the conditions again whether continue to execute or not.
repeat   {
    // Do something here
    // After that, continue to check conditions whether continue to run this block or not.
} while (condition)

import Foundation

func repeatWhileExample()    { 
    print("Repeat-While loop example")
    
    // Declare a variale x and assign value of 2
    var x = 2
    
    // Execute block at least once.
    // After each execution of the block,
    // It will check the condition, 
    // if the condition is still true, the block will be executed.
    repeat    {
        print("Value of x = \(x)") 
        x = x + 3; 
    } while (x < 10) 
}

import Foundation 

func loopBreakExample()    { 
    print("Break example"); 
    // Declare a variable and assign value of 2
    var x = 2; 
    while (x < 15)     { 
        print("----------------------");
        print("x = \(x)"); 
        // If x = 5 then exit the loop.
        if (x == 5)  {
            break;
        }
        // Increase value of x by 1.
        x = x + 1;
        print("After +1, x = \(x)"); 
    } 
}

import Foundation

func loopContinueExample()  { 
    print("Continue example") 
    // Declare a variable and assign value of 2
    var x = 2 
    while (x < 7) { 
        print("----------------------")
        print("x = \(x)") 
        // % is used for calculating remainder
        // If x is even, then ignore the command line below of 'continue'
        // and start next iteration (If conđition is still true).
        if (x % 2 == 0)  {
            // Increase x by 1.
            x = x + 1
            continue
        }
        else {
            // Increase x by 1.
            x = x + 1
        }
        print("After +1, x = \(x)") 
    }
}

// Way 1:
// Declare an array of int, specifies the elements.
var years: [Int] = [ 2001, 2003, 2005, 1980, 2003 ];

// Or (Inferred as array of Int):
var years = [ 2001, 2003, 2005, 1980, 2003 ];  

// Way 2:
// Declare an array of Floats, 
// 3 elements, all elements have value of 0.
var salaries:[Float] = [Float](count: 3,repeatedValue :0 );

// Or:
var salaries  = [Float](count: 3,repeatedValue :0 );

// Way 3:
// Declare a empty array (Have no elements)
var emptyArray:[Int] = [Int]()

import Foundation

func arrayExample1()  { 
    // Way 1:
    // Declare an array of Int, specifies the elements.
    var years: [Int] = [ 2001, 2003, 2005, 1980, 2003 ]; 
    print("--- years --- ");
    
    // count is a property of the array, it returns the number of elements.
    print("Element count of array years = \(years.count)");
    
    // Use a for loop to print out the elements of the array.
    for (var i = 0; i < years.count; i = i + 1) {
        print("Element at \(i) =  \(years[i])");
    } 
    print("--- salaries --- ");
    
    // Way 2:
    // Declare an array of Floats, 3 elements, all elements have value of 0.
    var salaries:[Float] = [Float](count: 3,repeatedValue :0 );
    
    // Assign values to the elements.
    salaries[0] = 1000;
    salaries[1] = 1200;
    salaries[2] = 1100;
    
    // Use a for loop to print out the elements of the array.
    for (var i = 0; i < salaries.count; i = i + 1) {
        print("Element at \(i) =  \(salaries[i])");
    }  
}

// Declare an array of String, with 2 elements.
var languages = ["Java","C#"]

// Using append() method to append element to ends of array.
languages.append("Swift")

// Can also use the += operator to append an array at the end.
languages += ["C/C++", "Perl"];

import Foundation 

func expaddingArrayExample()  { 
    // Declare an array of String, with 2 elements.
    var languages = ["Java","C#"] 
    // Using append() method to append element to ends
    languages.append("Swift")
    
    // Can also use the += operator to append an array at the end.
    languages += ["C/C++", "Perl"];
    
    // Using for-in loop.
    for lang in languages { 
        print("Language: " + lang)
    } 
}

import Foundation
import Cocoa

func enumerateArrayExample()  {
    
    // Declare an array of String with 3 elements.
    var languages :[String] = ["Java", "C#", "Swift"]
    
    
    
    for  (index, element )  in languages.enumerate()  {
        
        print("Element at \(index) = \(element)");
    }
    
}