Calculate hourly employee pay including overtime

Null-safety
val a: String? = null
println(a?.length())

Null-safety
val a: String? = null
println(a?.length())
> null

Null-safety
int length = a != null ? a.length() : -1

Null-safety
Null check

Null-safety
Assignmentselector

Null-safety
var length = if (a != null) a.length() else -1

Null-safety
Null check

Null-safety
Assignmentselector

Null-safety
var length = a?.length() ?: -1

Null-safety
Null check

Null-safety
Assignmentselector

Smart casts
if (x is String) {
print(x.length())
}

Smart casts
if (x is String) {
print(x.length())
}
Typecheck

Smart casts
if (x is String) {
print(x.length())
}
Smart cast

Smart casts
if (x !is String) {
return
}
print(x.size())

Smart casts
if (x !is String) {
return
}
print(x.size())Type check

Smart casts
if (x !is String) {
return
}
print(x.size())
Smart cast

Smart casts
if (x !is String || x.size() == 0) {
return
}

Smart casts
return
}
Typecheck

Smart casts
return
}
Smart cast

Smart casts
if (x is String && x.size() > 0) {
print(x.size())
}

Smart casts
print(x.size())
}
Typecheck

Smart casts
print(x.size())
}
Smart cast

Smart casts
when (x) {
is Int -> print(x + 1)
is String -> print(x.size() + 1)
is Array<Int> -> print(x.sum())
}

Smart casts
Typecheck
when (x) {
}

Smart casts
Smart cast
when (x) {
}

Smart casts
when (x) {
}
Typecheck

Smart casts
when (x) {
}
Smart cast

Smart casts
when (x) {
}
Type check

String templates
val apples = 4
println("I have " + apples + " apples.")
> I have 4 apples.

String templates
val apples = 4
println("I have $apples apples.")
> I have 4 apples.
> I have 4 apples.

String templates
val apples = 4
val bananas = 3
println("I have $apples apples and " + (apples + bananas) + " fruits.")
> I have 4 apples.
> I have 4 apples.
> I have 4 apples and 7 fruits.

String templates
val apples = 4
val bananas = 3
println("I have $apples apples and ${apples+bananas} fruits.")
> I have 4 apples.

Range expressions
if (1 <= i && i <= 10) {
println(i)
}

Range expressions
if (1 <= i && i <= 10) {
println(i)
}
if (IntRange(1, 10).contains(i)) {
println(i)
}

Range expressions
if (1 <= i && i <= 10) {
println(i)
}
if (1.rangeTo(10).contains(i)) {
println(i)
}

Range expressions
if (1 <= i && i <= 10) {
println(i)
}
if (i in 1..10 ) {
println(i)
} Range operator

Range expressions
for (i in 1..4) {
print(i)
}
> 1234

Range expressions
for (i in 1..4 step 2) {
print(i)
}
> 1234
> 13

Range expressions
for (i in 4 downTo 1 step 2) {
print(i)
}
> 1234
> 13
> 42

Range expressions
for (i in 1.0..2.0) {
print("$i ")
}
> 13
> 42
> 1.0 2.0

Range expressions
for (i in 1.0..2.0 step 0.3) {
print("$i ")
}
> 42
> 1.0 2.0
> 1.0 1.3 1.6 1.9

Lab 1
Foo Corporation needs a program to calculate how much to pay their hourly employees. The US Department
of Labor requires that employees get paid time and a half for any hours over 40 that they work in a single
week. For example, if an employee works 45 hours, they get 5 hours of overtime, at 1.5 times their base pay.
The State of Massachusetts requires that hourly employees be paid at least $8.00 an hour. Foo Corp requires
that an employee not work more than 60 hours in a week.
• Rules
• An employee gets paid (hours worked) × (base pay), for each hour up to 40 hours.
• For every hour over 40, they get overtime = (base pay) × 1.5.
• The base pay must not be less than the minimum wage ($8.00 an hour). If it is, print an error.
• If the number of hours is greater than 60, print an error message.
Write a method that takes the base pay and hours worked as parameters, and prints the total pay
or an error. Write a main method that calls this method for each of these employees:
Base Pay Hours Worked
Employee 1 $7.50 35
Employee 2 $8.20 47
Employee 3 $10.00 73

Lab 2
A group of ITI friends decide to run a Marathon. Their names and times (in minutes) are below:
Name Time (minutes)
Ahmed 341
Mohamed 273
Ismail 278
Hend 329
Aly 445
Hossam 402
Ola 388
Alaa 275
Basma 243
Mina 334
Nada 412
Saad 393
• Find the fastest runner. Print the name and his/her time (in minutes).
• Optional: Find the second fastest runner. Print the name and his/her time (in minutes).

Lab 3
• Create an Android a simple app with two buttons, one to count and
one to show a toast.

Lab 4
• Create an Android UI with one text field, centered at the top of the screen, and
one button. The text field will initially display the text Tap to Change Color.
• Every time you tap the button, you will generate a random color using RGB
values, change the text to that color, and display the values for the color in the
following format (assuming you are displaying a light grey with values
100/100/100): COLOR: 100r, 100g, 100b.

Lab 5
• Battery Status App
• Create an Android App that displays a colored
bar to display the battery's status.
• Display a battery drawable as follows:
0-25% - Red (battery low)
>25% <80% - Yellow (battery medium)
>80% - Green (battery good)

When expression
• When expression is similar to switch/case in Java,
but far more powerful.

When expression
when (argument) {
match1 -> fun1()
match2 -> fun2()
else -> fun3()
}

When expression
when (argument) {
m a t c h 1 - > f u n 1 ( )
m a t c h 2 - > f u n 2 ( )
e l s e - > f u n 3 ( )
}
Can be anything

When expression
( a r g u m e n t )
Match1 -> fun1()
match2 -> fun2()
e l s e - > f u n 3 ( )
}
Can be anything

When expression
var result: Int = when (argument) {
m a t c h 1 - > f u n 1 ( )
m a t c h 2 - > f u n 2 ( )
e l s e - > f u n 3 ( )
}
Can return result

When expression
var result: Int = when (argument) {
match1 -> fun1()
match2 -> fun2()
else -> fun3()
}

When expression
override fun onCreateViewHolder(g: ViewGroup, type: Int) {
when (type) {
TYPE_TITLE -> TitleViewHolder(g)
TYPE_DESCRIPTION -> DescriptionViewHolder(g))
}
return null
}

When expression
o v e r r i d e f u n o n C r e a t e V i e w H o l d e r ( g : V i e w G r o u p ,
t y p e : I n t ) {
when (type) {
T Y P E _ T I T L E - > T i t l e V i e w H o l d e r ( g )
T Y P E _ D E S C R I P T I O N - >
D e s c r i p t i o n V i e w H o l d e r ( g ) )
}
r e t u r n n u l l
}
Can be placed after a = symbol

When expression
override fun onCreateViewHolder(g: ViewGroup, type: Int) = when (type) {
T Y P E _ T I T L E - > T i t l e V i e w H o l d e r ( g )
T Y P E _ D E S C R I P T I O N - >
D e s c r i p t i o n V i e w H o l d e r ( g ) )
e l s e - > n u l l
}

When expression
override fun onCreateViewHolder(g: ViewGroup, type: Int) = when (type) {
TYPE_TITLE -> TitleViewHolder(g)
TYPE_DESCRIPTION -> DescriptionViewHolder(g)
else -> null
}

When expression
override fun getItemViewType(index: Int) = when (dataList[index]) {
is Title -> TYPE_TITLE
is Description -> TYPE_DESCRIPTION
else -> TYPE_UNDEFINED
}

When expression
override fun getItemViewType(index: Int) = when (dataList[index]) {
is Title -> TYPE_TITLE
is Description -> TYPE_DESCRIPTION
else -> TYPE_UNDEFINED
}
Type checks possible

When expression
override fun onBindViewHolder(viewHolder: ViewHolder, index: Int) {
val displayable: Displayable = dataList[index]
when (displayable) {
is Title -> initTitle(viewHolder, displayable)
is Description -> initDescription(viewHolder, displayable)
}
}

When expression
o v e r r i d e f u n o n B i n d V i e w H o l d e r ( v i e w H o l d e r : V i e w H o l d e r , i n d e x : I n t ) {
v a l d i s p l a y a b l e : D i s p l a y a b l e = d a t a L i s t [ i n d e x ]
W h e n ( d i s p l a y a b l e ) {
is Title -> initTitle(viewHolder, displayable)
is Description -> initDescription(viewHolder, displayable)
}
}
Smart cast

let, apply, use, with
• Higher-order functions - function that takes
functions as parameters, or returns a function.

let (scope function)
/**
* Calls the specified function [block] with `this` value as
* its argument and returns its result.
*/
public inline fun <T, R> T.let(block: (T) -> R): R = block(this)

let
Preferences.getUser().let {
showUserName(it.name)
showUserEmail(it.email)
}

let
}
Refers to user object

let
}
Variable visibility scope

let
Preferences.getUser()?.let {
}
Only execute if user is not null

let
Preferences.getUser()?.let {
}

use (try with resources function)
/**
* Executes the given [block] function on this resource and then
* closes it down correctly whether an exception is thrown or not.
*/
public inline fun <T : Closeable, R> T.use(block: (T) -> R): R {
var closed = false
try {
return block(this)
} catch (e: Exception) {
// ommitted
} finally {
if (!closed) { close()
}
}
}

use
fun countUsers(): Long {
val database = openDatabase()
val result = database.count("users")
database.close()
return result
}

use
fun countUsers() = openDatabase().use { it.count("users") }
Automatically close
database

Refers to database object
use

use

with
/**
* Calls the specified function [block] with the given [receiver]
* as its receiver and returns its result.
*/
public inline fun <T, R> with(receiver: T, block: T.() -> R): R = receiver.block()

with
recyclerView.setHasFixedSize(true)
recyclerView.addItemDecoration(createDecorator())
recyclerView.layoutManager = LinearLayoutManager(applicationContext)
recyclerView.adapter = myAdapter

with
with(recyclerView) {
}

with
}
Not need

with
setHasFixedSize(true)
addItemDecoration(createDecorator())
layoutManager = LinearLayoutManager(applicationContext)
adapter = myAdapter
}

apply
/**
* Calls the specified function [block] with `this` value as its receiver
* and returns `this` value.
*/
public inline fun <T> T.apply(block: T.() -> Unit): T { block(); return this }

apply
fun makeDir(path: String): File {
val result: File = File(path)
result.mkdirs()
return result
}

apply
fun makeDir(path: String) = File(path).apply { mkdirs() }

Collections
val numbers: MutableList<Int> = mutableListOf(1, 2, 3)
numbers.add(1)
val numbers2: List<Int> = listOf(1, 2, 3)
numbers2.add(1)
No such method

Collections
mutableListOf(1, null, 2, null, 3, 4, 5, 6, 7, 8, 9)
.filterNotNull()
.filter { it % 2 == 0 }
.sortedDescending()
> [1, null, 2, null, 3, 4, 5, 6, 7, 8, 9]

Collections
.filterNotNull()
.filter { it % 2 == 0 }
.sortedDescending()
> [1, 2, 3, 4, 5, 6, 7, 8, 9]

Collections
.filterNotNull()
.filter { it % 2 == 0 }
.sortedDescending()
> [2, 4, 6, 8]

Collections
.filterNotNull()
.filter { it % 2 == 0 }
.sortedDescending()
> [8, 6, 4, 2]

Collections
getOrElse()
find()
filter()
filterNot()
filterNotNull()
flatMap()
take()
takeLast()
sortBy()
sortByDescending()
groupBy()
map()
mapNotNull()
all()
any()
maxBy()
minBy()
minWith()
sumBy()
zip()
...

Default values for function parameters
• Function parameters can have default values, which are used when a
corresponding argument is omitted.
• This allows for a reduced number of overloads compared to other
languages.

fun query(table: String,
columns: Array<String>,
selection: String?,
selectionArgs : Array<String>?,
orderBy: String?): Cursor {
...
}
// function call
query("USERS", arrayOf("ID", "NAME"), null, null, "NAME")

selection: String? = null,
selectionArgs : Array<String>? = null,
orderBy: String? = null): Cursor {
...
}
// function call
Default value

...
}
// function call

...
}
// function call
query("USERS", arrayOf("ID", "NAME"), null, null, orderBy = "NAME")
Named argument

...
}
// function call
query("USERS", arrayOf("ID", "NAME"), null, null, orderBy = "NAME")
Not needed

...
}
// function call
query("USERS", arrayOf("ID", "NAME"), orderBy = "NAME")

Lazy property
• Value gets computed only upon first access.

Lazy property
val preference = getSharedPreferences("pref")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val username = preference.getString("username")
}

Lazy property
val preference = getSharedPreferences("pref")
}
Crash, require context

Lazy property
val preference by lazy { getSharedPreferences("pref") }
}
Won’t be executed until the
property is first used

Lazy property
val preference by lazy { getSharedPreferences("pref") }
}

Extension functions
public fun isLollipopOrGreater(code: Int): Boolean {
return code >= Build.VERSION_CODES.LOLLIPOP
}

Extension functions
public fun Int.isLollipopOrGreater(code: Int): Boolean {
}

Extension functions
public fun Int.isLollipopOrGreater(): Boolean {
}

Extension functions
public fun Int.isLollipopOrGreater(): Boolean {
return this >= Build.VERSION_CODES.LOLLIPOP
}

Extension functions
public fun Int.isLollipopOrGreater(): Boolean {.
}
if (Build.VERSION.SDK_INT.isLollipopOrGreater) {
// ...
}

Extension functions
public fun Int.isLollipopOrGreater(): Boolean {.
}
if (16.isLollipopOrGreater) {
// ...
}

Extension functions
Function<Customer, Order> customerMapper = // ...
Function<Order, Boolean> orderFilter = // ...
Function<Order, Float> orderSorter = // ...
List<Order> vipOrders = sortBy(filter(map(customers,
customerMapper),
orderFilter),
orderSorter);

Extension functions
Function<Customer, Order> customerMapper = // ...
Function<Order, Boolean> orderFilter = // ...
Function<Order, Float> orderSorter = // ...
List<Order> vipOrders = sortBy(filter(map(customers,
customerMapper,
orderFilter),
orderSorter);

Extension functions
val vipOrders = customers
.map { it.lastOrder }
.filter { it.total >= 500F }
.sortBy { it.total }

Primary constructors
class Customer {
var firstName: String = // ...
var lastName: String = // ...
var email: String = // ...
}

class Customer(firstName: String, lastName: String, email: String) {
}

var firstName: String = firstName
var lastName: String = lastName
var email: String = email
}

var firstName: String
var lastName: String
var email: String
init {
this.firstName = firstName
this.lastName = lastName
this.email = email
}
}

class Customer(firstName: String, lastName: String, email: String)

class Customer(var firstName: String, var lastName: String, var email: String)

class Customer(
var firstName: String,
var lastName: String,
var email: String)

class Customer(
val firstName: String,
val lastName: String,
val email: String)

Properties
class Customer {
private String firstName;
private String lastName;
private String email;
public String getFirstName() { return firstName;}
public String getLastName() { return lastName; }
public String getEmail() { return email; }
public void setFirstName(String firstName) { this.firstName = firstName }
public void setLastName(String lastName) { this.lastName = lastName }
public void setEmail(String email) { this.email = email }
}

Properties
class Customer {
}

Properties
class Customer {
}
val customer = Customer()
customer.firstName = "Michael"
customer.lastName = "Pardo"
customer.email = "michael@michaelpardo.com"

Data class
What it does?
Nothing, just hold data
What it provides?
● getters, setters
● equals()/hashCode()
● toString() ofthe form"User(name=John, age=42)"
● copy() function

Data class
data class User(val name: String, val age: Int)

Data class
data class User(val name: String, val age: Int)
val user = User("Dmytro", 24)
print(user)
> User(name=Dmytro, age=24)

Singletons
public class Singleton {
private static volatile Singleton instance;
private Singleton() { }
public static Singleton getInstance() {
if (instance == null ) {
synchronized (Singleton.class) {
if (instance == null) {
instance = new Singleton();
}
}
}
return instance;
}
}

Singletons
private static volatile Singleton instance = null;
public static synchronized Singleton getInstance() {
if (instance == null) {
}
return instance;
}
}

Singletons
private static final Singleton INSTANCE = new Singleton();
private Singleton() {}
return INSTANCE;
}
}

Singletons
private static final Singleton instance;
static {
try {
} catch (Exception e) {
throw new RuntimeException("an error occurred!", e);
}
}
return instance;
}
}

Singletons
private static class SingletonHolder {
private static final Singleton INSTANCE = new Singleton();
}
return SingletonHolder.INSTANCE;
}
}

Singletons
object Logger {
val tag = "TAG"
fun d(message: String) {
Log.d(tag, message)
}
}

Companion objects
class LaunchActivity extends AppCompatActivity {
public static final String TAG = LaunchActivity.class.getName();
public static void start(Context context) {
context.startActivity(new Intent(context, LaunchActivity.class));
}
}

Companion objects
}
}
Timber.v("Starting activity %s", LaunchActivity.TAG);

Companion objects
}
}
Timber.v("Starting activity %s", LaunchActivity.TAG);
LaunchActivity.start(context);

Companion objects
class LaunchActivity {
companion object {
val TAG: String = LaunchActivity::class.simpleName
fun start(context: Context) {
context.startActivity(Intent(context, LaunchActivity::class))
}
}
}

Companion objects
companion object {
}
}
}
Timber.v("Starting activity ${LaunchActivity.TAG}")

Companion objects
companion object {
}
}
}
Timber.v("Starting activity ${LaunchActivity.TAG}")
LaunchActivity.start(context)

Calculate hourly employee pay including overtime

Recommended

Recommended

More Related Content

What's hot

What's hot (14)

Similar to Calculate hourly employee pay including overtime

Similar to Calculate hourly employee pay including overtime (20)

Recently uploaded

Recently uploaded (20)

Calculate hourly employee pay including overtime