Code Review Flashcards

Question

List out 3 naming conventions for Variable Names

Answer 1

1. The first character must be a letter ( upper / lowercase ) or an underscore ( _ ) 2. Name cannot contain spaces 3. Don't use C# Keywords or Reserved Words

Answer 2

productLabel.Text = productDescription MessageBox.Show(productLabel)

Answer 3

string message message = "Hello" + "World" MessageBox.Show(message)

Answer 4

1. No, because string myName is a **local variable** inside firstButton_Click

Answer 5

string firstName, middleName, lastName; firstName = "Leon"; middleName = "Scott"; lastName = "Kennedy"; MessageBox.Show($"The character you played as in RE4 is : {firstName} {middleName} {lastName}");

Answer 6

1. The semicolon ( ; ) when the C# code ends string firstName = "Leon"**;**

Answer 7

1. int 2. double 3. float 4. boolean 5. char 6. array 7. list 8. null 9. decimal

Answer 8

1. int is treated as double and the result is double

Answer 9

int x = 5; int y = 4; MessageBox.Show((x+y).ToString());

Answer 10

1. int.Parse() 2. double.Parse() 3. decimal.Parse()

Answer 11

int hoursWorked = int.Parse(hoursWorkedTextBox1.Text);

Answer 12

1. Catch FormatException error * To solve this error, we can use Int.TryParse or double.TryParse ``` double hoursWorked; if (double.TryParse(hoursWorkedTextBox1.Text, out hoursWorked)) { MessageBox.Show("You entered: " + hoursWorked); } else { MessageBox.Show("Please enter a valid number."); } ```

Answer 13

1. .ToString() method

Answer 14

int myNumber = 123; MessageBox.Show(myNumber.ToString()); * Will get cannot convert from 'int' to 'string' when .ToString() isn't with myNumber in MessageBox

Answer 15

double x = 12.3; MessageBox.Show(x.ToString(**"n3"**)); * Use "n3" inside .ToString()

Answer 16

int x = 123; MessageBox.Show(x.ToString(**"f2"**)); * Use "f2" inside .ToString()

Answer 17

double x = 12.3; MessageBox.Show(x.ToString(**"e3"**)); * Use "e3" inside .ToString()

Answer 18

double x = 12.3; MessageBox.Show(x.ToString(**"C"**)); * Use "C" inside .ToString()

Answer 19

double x = .234; // Same as 0.234 MessageBox.Show(x.ToString(**"P"**)); * Use "P" inside .ToString()

Answer 20

1. A panel cannot display a title and does not have a Text property, but a GroupBox supports these 2 properties 2. A panel's border can be specified by its BorderStyle property, while the GroupBox cannot be

Answer 21

1. BackgroundImage

Answer 22

1. Web 2. System 3. Custom

Answer 23

1. Go to Text property and type &Exit 2. Then add code ``` public void exitButton_Click (object sender, EventArgs e ) { this.Close(); } ```

Answer 24

1. Math.PI 2. Math.E

Answer 25

1. Math.Sqrt(x);

Answer 26

1. Math.Pow(x,y) x = 2 , y = 3 will be 2³ = 8

Answer 27

1. Is an unexpected error that happens while a program is running * Will abruptly halt if an exception is not handled by the program

Answer 28

try {} catch {}

Answer 29

``` try { int age; age = int.Parse(txtAge.Text); } catch { MessageBox.Show("Invalid Value Entered") } ```

Answer 30

const int myBirthYear = 2003; * a constant variable represents a value that cannot be changed during the program's execution

Answer 31

``` public partial class Form1: { private string name = "Jack"; public Form1() { InitializeComponent(); } private void showNameButton_Click(object sender, EventArgs e) { MessageBox.Show(name); } private void chrisButton_Click(object sender, EventArgs e) { name="Chris"; } } ``` * Think of Fields as **Global Variable** inside this class

Answer 32

``` MessageBox.Show("Are you sure?" , "Logout" , MessageBoxButtons.OkCancel, MessageBoxIcon.Question); ```

Answer 33

1. > - Greater than 2. < - Less than 3. >= - Greater than or equal to 4. <= - Less than or equal to 5. == - Equal to 6. != - Not equal to

Answer 34

``` int temp = (int) numTemp.Value; if ( temp >= 40 ) { MessageBox.Show("Hot"); } else if ( temp < 40 && temp >= 10 ) // or ( temp >= 10 ) is enough { MessageBox.Show("Ok"); } else { MessageBox.Show("Cold"); } ```

Answer 35

1. && - And 2. || - Or 3. ! - Not

Answer 36

``` int month_num = ( int ) numMonth.Value ; switch ( month_num ) { case 1: MessageBox.Show("January"); break; case 2: MessageBox.Show("February"); break; case 3: MessageBox.Show("March"); break; case 4: MessageBox.Show("April"); break; case 5: MessageBox.Show("May"); break; case 6: MessageBox.Show("June"); break; case 7: MessageBox.Show("July"); break; case 8: MessageBox.Show("August"); break; case 9: MessageBox.Show("September"); break; case 10: MessageBox.Show("October"); break; case 11: MessageBox.Show("November"); break; case 12: MessageBox.Show("December"); break; default: MessageBox.Show("No month found"); break; } ``` * Break statement in every case is a must or it will run all statement at each case * Another method using Array ``` string[] months = { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" }; int monthIndex = (int)numMonth.Value; // 1 through 12 if (monthIndex >= 1 && monthIndex <= 12) { MessageBox.Show(months[monthIndex - 1]); } else { MessageBox.Show("No month found"); } ```

Answer 37

``` string name1 = "Mary"; string name2 = "Mark"; if ( String.Compare(name1, name2) == 0 ) { MessageBox.Show("Both are the same name") } else { MessageBox.Show("Both name are not the same") } ``` * String.Compare **returns 0** when the two strings are exactly equal. * For case sensitive checking ``` String.Compare(name1, name2, StringComparison.OrdinalIgnoreCase) == 0 ```

Answer 38

int age; if ( int.TryParse(inputAge.Text , out age) ) { MessageBox.Show($"You are {age} years old") } else { MessageBox.Show("Invalid age input") } * Also have **double.TryParse()** and **decimal.TryParse()**

Answer 39

1. Process of inspecting data that has been entered into a program to make sure it is valid before it is used if ( textScore >= 0 && textScore <= 100 )

Answer 40

1. Radio buttons can only choose one from several possible choices, while Check Boxes can select multiple options

Answer 41

``` if ( rdrMale.Checked ) { MessageBox.Show("Male"); } else if ( rdrFemale.Checked ) { MessageBox.Show("Female"); } ``` or ``` MessageBox.Show(rdrMale.Text); ```

Answer 42

1. CheckedChanged

Answer 43

``` private void Form1_Load(object sender, EventArgs e) { // Add items to the ListBox when the form loads listBoxFruits.Items.Add("Apple"); listBoxFruits.Items.Add("Banana"); listBoxFruits.Items.Add("Cherry"); listBoxFruits.Items.Add("Durian"); listBoxFruits.Items.Add("Elderberry"); } private void btnShowSelected_Click(object sender, EventArgs e) { // Check if an item is selected if (listBoxFruits.SelectedItem != null) { MessageBox.Show($"You selected: {listBoxFruits.SelectedItem.ToString()}"); } else { MessageBox.Show("Please select a fruit first!"); } } ``` ``` if ( listBoxFruit.SelectedIndex == -1 ) { MessageBox.Show("Nothing Selected") } ``` ``` listBoxFruits.Items.Clear(); ```

Answer 44

``` for ( int i = 0 ; i < 5 ; i ++ ) { MessageBox.Show("Hello") } ```

Answer 45

``` for ( int i = 1 ; i <= 100 ; i++ ) { MessageBox.Show(i.ToString()); } ```

Answer 46

``` for ( int i = 100 ; i <= 1 ; i-- ) { MessageBox.Show(i.ToString()); } ```

Answer 47

1. for loop 2. while loop

Answer 48

1. do-while loop

Answer 49

``` int i = 0 ; while ( i < 5 ){ MessageBox.Show("Hello"); i++ ; } ``` Omitting i ++ will be showing **Hello** Infinitely

Answer 50

1. 10 - a-- means show a then only -1 2. 9 - since a is shown, a is then -1 and assigned to b 3. 9 4. 8

Answer 51

1. 9 2. 8 3. 9 4. 8 - Show b first then only + 1

Answer 52

1. Postfix Mode 2. Prefix Mode

Answer 53

int i = 1 ; do { MessageBox.Show("Hello"); i ++ ; } while ( number <= 2 ) ;

Answer 54

``` private void myButton_Click(object sender, EventArgs e) { ReturnAge(); } private void ReturnAge(){ const int currentYear = DateTime.Now.Year; try { int birthYear = int.Parse(txtYear.Text); int age = currentYear - birthYear; MessageBox.Show(age.ToString()); } catch(Exception e){ MessageBox.Show("Invalid Birth Year") } } ```

Answer 55

``` private void myButton_Click(object sender, EventArgs e) { const int currentYear = DateTime.Now.Year; int birthYear; if ( int.TryParse(txtAge.Text, out birthYear) ) { } else { MessageBox.Show("Invalid Birth Year") return; } int age = ReturnAge(currentYear, birthYear); MessageBox.Show(age.ToString()); } private int ReturnAge(int currentYear, int birthYear){ int age = currentYear - birthYear; return age; } ```

Answer 56

1. private 2. public

Answer 57

1. Argument 2. Paramter

Answer 58

``` int sum = SumTwoValue ( 1 , 2 ) // Arguments private int SumTwoValue ( int a , int b ) { // Parameter return a + b ; } ```

Answer 59

``` // 2 is overiding the default argument int sum = SumTwoValue ( 1 , 2 ) // Arguments , Ans = 3 int sum = SumTwoValue ( 1 ) // Arguments , Ans = 5 private int SumTwoValue ( int a , int b = 4 ) { // Parameter return a + b ; } ```

Answer 60

``` private void btn1_Click(object sender, EventArgs e) { int age; showAge(out age); MessageBox.Show($"Age : {age}") } private void showAge(out int age) { int currentYear = DateTime.Now.Year; int birthYear = int.Parse( txtYear.Text ) age = currentYear - birthYear } ```

Answer 61

int myVar = 99; SetToZero(ref myVar); private void SetToZero(ref int number) { number = 0 ; }

Answer 62

``` const int size = 5; int[] numAry = new int[size]; numAry[0] = 1; numAry[1] = 2; numAry[2] = 3; numAry[3] = 4; numAry[4] = 5; // This line will cause an error: numAry[5] = 6; // IndexOutOfRangeException ``` * We can also do the easy way int[] numAry = new int[] {1,2,3,4,5}

Answer 63

int[] numAry = new int[] {1,2,3,4,5} for ( int i = 0 ; i < numAry.Length ; i ++ ) { MessageBox.Show($"{numAry[i]}"); } // or foreach ( int num in numAry ) { MessageBox.Show($"{num}"); }

Answer 64

``` const int size = 5; int[] numAry = new int[size]; int assignNum = 5; for ( int i = 0 ; i < numAry.Length ; i++ ) { numAry[i] = assignNum; asignNum--; } ```

Answer 65

``` int[] numAry = {1 , 2 , 3 , 4 , 5}; MessageBox.Show(numAry.Length.ToString()); ```

Answer 66

``` int[] numbers = { 1 , 2 , 3 , 4 , 5 } foreach ( int num in numbers ) { MessageBox.Show(num.ToString()); } ```

Answer 67

``` int[] numAry = { 1, 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 }; // Passed in the array and want the method to found 7 inside the array searchAry( numAry , 7) MessageBox.Show("7 is {searchAry().ToString()} inside the array"); private void searchAry( int[] ary , int val ) { bool found = false; int index = 0 ; int position = 0; while ( !found && index < ary.Length) { if ( ary[index] == val ) { found = true; position = index; MessageBox.Show($"{val} is found inside the array, and the position is at {position}"); } index ++ ; } } ```

Answer 68

``` int[] numAry = {10, 20 , 1, 2 , 3}; int total = 0; foreach ( int val in numAry ) { total += val; } MessageBox.Show(total.ToString()); ```

Answer 69

``` int[] numAry1 = {1 , 2 , 3 , 4 , 5 }; int[] numAry2 = {1 , 2 , 3 , 4 , 5 , 5 }; bool check = checkAryLength(numAry1, numAry2) ; if ( !check ) { MessageBox.Show("Both array length is not the same"); } else { MessageBox.Show("Both array length is the same") } private bool checkAryLength( int[] ary1 , int[] ary2 ) { return ary1.Length == ary2.Length } ```

Answer 70

``` int[] numAry1 = {1 , 2 , 3 , 4 , 5 }; int[] numAry2 = new int[numAry1.Length]; copyAry(numAry1 , numAry2); private void copyAry ( int[] ary1 , int[] ary2 ) { for ( int i = 0 ; i < ary1.Length ; i ++ ) { ary2[i] = ary1[i]; } } ```

Answer 71

``` int[] numAry = {10, 20 , 1, 2 , 3}; int highestVal = HighestVal(numAry); MessageBox.Show($"The highest value inside the array is {highestVal}"); private int HighestVal( int[] ary1 ) { int highest = ary1[0]; for ( int i = 0; i < ary1.Length ; i ++ ) { if ( ary1[i] >= highest ) { = ary1[i]; } return lowest; } } ```

Answer 72

``` int[] numAry = {10, 20 , 1, 2 , 3}; int lowestVal = LowestVal(numAry); MessageBox.Show($"The lowest value inside the array is {lowestVal}"); private int LowestVal( int[] ary1 ) { int lowest = ary1[0]; for ( int i = 0; i < ary1.Length ; i ++ ) { if ( ary1[i] <= lowest ) { lowest = ary1[i]; } return lowest; } } ```

Answer 73

``` List numList = new List(); // 1. Add Items numList.Add(11); numList.Add(28); numList.Add(35); // 2. Copy List Items foreach ( int val in numList ) { lstOutput.Items.Add(val); } // 3. Insert 53 numList.Insert(2,53); // 4. Remove index 4 numList.RemoveAt(4); // 5. Remove number 11 numList.Remove(11); // 6. Reverse the list numList.Reverse(); // 7. Sort the list in Ascending order numList.Sort(); // 8. Find number 28 and return boolean values bool find = numList.Contains(28); // 9. Clear the lit numList.Clear(); ```

Answer 74

``` // 7. Call Class , Object Student student1 = new Student("Mark" , "Male" , "80") student1.printDetails(); double cgpa = student1.calculateCGPA(); MessageBox.Show($"CGPA : {cgpa}") class Student { // 2. Add Field private string _name { get; set; } ; private string _gender { get; set; } ; private int _mark { get; set; } ; // 5. Add Constructor public Student() { } // 6. Constructor Overloading public Student ( string name, string gender , int mark ) { _name = name; _gender = gender; _mark = mark; } // 3. Print Details method public void printDetails(){ MessageBox.Show($"Name ; {_name} , Gender : {_gender} , Mark : {_mark}"); } // 4. Calculate CGPA public double calculateCGPA(){ if ( _mark >= 80 ) { return 4.0; } // Other Logic here } } ```

Answer 75

1. Same name as class 2. No return type 3. Assign value to member field 4. Can have none or many constructor

Answer 76

``` Student student = new Student(); ShowStudentStatus(student); private void ShowStudentStatus( Student student ) { MessageBox.Show("Details : " + students.DisplayDetails()); } ```

Answer 77

1. Backing field * It backs the public field

Answer 78

``` class Pet { // 2. private string _name; // 1. public Pet(){ _name = ""; } // 3. public string Name { get { return _name; } set { _name = value; } } } // 4. Pet pet = new Pet(); // Calls the set accessor and sets _name = "Fluffy" pet.Name = "Fido" ; // Calls the get accessor and returns "Fido" string petName = myPet.Name; ``` * private backing field is set to private to protect it from accidental corruption * To create a **Read-Only Properties**, remove the **set accessor**

Answer 79

1. Remove the set accessor inside the public properties public string Name { get { return _name; } }

Answer 80

1. Parameterized Constructor 2. Overloaded Methods ``` public void Deposit(decimal amount) { } public void Deposit(double amount) { } // overloaded public void Deposit(int numbers,string name) { } // overloaded public void Deposit(string names) { } // overloaded ```

Answer 81

``` // Access Form Class Dashboard adminDashboard = new Dashboard(staffId , this); // Show the AdminDashboard form adminDashboard.Show(); // Hide the Login Page this.Hide(); ```

Code Review Flashcards

(112 cards)