Code Review Flashcards
1
Q
What property is being used to change the background color for every element?
A
- BackColor
2
Q
What property is being used to set the element’s variable name?
A
- Name ( in Design )
3
Q
List out 5 values for image size mode
A
- Zoom
- StretchImage
- Normal
- AutoSize
- CenterImage
4
Q
List out 2 values for the Visible property
A
- True
- False
5
Q
How to change the element text shown at the UI?
A
- Change the text at the Text property
6
Q
List out 9 properties for Text Alignment
A
- Top Left
- Top Center
- Top Right
- Middle Left
- Middle Center
- Middle Right
- Bottom Left
- Bottom Center
- Bottom Right
7
Q
What property is set to ensure that the elements doesn’t relocate when the windows expand or shrink?
A
- Anchor
8
Q
What property is being used to change the text color?
A
- ForeColor
9
Q
What property in TextBox is used to hide the letters input?
A
- PasswordChar
- Example
When set to *
Input 1234 will turn **
10
Q
List out 5 types of events
A
- Activate Events
- Selects item on screen
- Changed Events
- Modified control property
- Focus Events
- Control gets or loses focus
- Key Events
- Interact with keyboard
- Mouse Events
- Interact with mouse
11
Q
How to show the dialog box the shows the message when a button is pressed?
A
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(“Hello”);
}
12
Q
What property allows changing the element’s text font, font style, and font size?
A
- Font
13
Q
List out 3 values that can be set in the BorderStyle
A
- None
- FixedSingle
- Fixed3D
14
Q
Which properties can be used to enable auto size method?
A
- AutoSize
15
Q
What is an assignment operator?
A
- =
16
Q
How to assign the text from label1 to another text Hello?
A
- label1.Text = “Hello”
17
Q
How to change the label1 background color to another color ( blue ) after a button is pressed?
A
private void button1_Click(object sender, EventArgs e)
{
label1.BackColor = Color.Blue ;
}
this.BackColor = Color.Red;
// Will change the background color for the current form
this inside a class means the current instance of the class
18
Q
How to use concatenation?
A
- Use the + operator on string value to combine 2 string
“Welcome” + “to C#”
1 + 1 = 2
“1” + “1” = 11
19
Q
List out how to write comment on
1. Single Line Comment
2. Multiline Comment
A
- //
- /**/
20
Q
What is identation being used for?
A
- Make code more human readable
21
Q
How to close the current application form when a button is clicked?
A
private void exitButton_Click(object sender, EventArgs e)
{
// Close the form.
this.Close();
}
22
Q
List out 3 types of error
A
- Syntax Errors
- Show with jagged line
- MessageBox.Sh(“Hi)
- Run-time Errors
- Errors when program runs
- num = 100 / 0
- Logic ( Semantic ) Errors
- age = 2024 + bornYear
23
Q
How to declare variable car to store string Perodua?
A
- string car = “Perodua”
24
Q
How to declare variable age with current year ( DateTime ) minus birth year ( txtBornYear ) ?
A
int birthYear = int.Parse(txtBornYear.Text);
static int currentYear = DateTime.Now.Year;
int age = currentYear - birthYear ;
Improvement with Error Checking
int birthYear;
if (int.TryParse(txtBornYear.Text, out birthYear))
{
int currentYear = DateTime.Now.Year;
int age = currentYear - birthYear;
MessageBox.Show(“You are “ + age + “ years old.”);
}
else
{
MessageBox.Show(“Please enter a valid year.”);
}
25
List out 3 naming conventions for Variable Names
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
26
How to assign string variable productDesciption value to label productLabel ?
productLabel.Text = productDescription
MessageBox.Show(productLabel)
27
Create a variable message then combine "Hello" and "World" and show it in Message Box
string message
message = "Hello" + "World"
MessageBox.Show(message)
28
Can I access string myName at the method secondButton_Click?
```
private void firstButton_Click(object sender, EventArgs e)
{
// Local variable
string myName;
myName = nameTextBox.Text;
}
private void secondButton_Click(object sender, EventArgs e)
{
outputLabel.Text = myName;
}
```
1. No, because string myName is a **local variable** inside firstButton_Click
29
How to declare firstName, middleName and lastName as a string variable in one line?
string firstName, middleName, lastName;
firstName = "Leon";
middleName = "Scott";
lastName = "Kennedy";
MessageBox.Show($"The character you played as in RE4 is : {firstName} {middleName} {lastName}");
30
What is the most important symbol in the exam?
1. The semicolon ( ; ) when the C# code ends
string firstName = "Leon"**;**
31
Which value cannot surround by double quote ( string ) ? ( 9 )
1. int
2. double
3. float
4. boolean
5. char
6. array
7. list
8. null
9. decimal
32
What is the final value when an operation involves an int and a double?
1. int is treated as double and the result is double
33
Is an operation involving a double and decimal is allowed?
1. No
34
How to perform 5 + 4 and pass it to message box ?
int x = 5;
int y = 4;
MessageBox.Show((x+y).ToString());
35
List out 3 methods to convert string to numeric data types
1. int.Parse()
2. double.Parse()
3. decimal.Parse()
36
How to parse label value from string to int ?
int hoursWorked = int.Parse(hoursWorkedTextBox1.Text);
37
What will happen when the hoursWorkedTextBox1 has value of "49.99"?
int hoursWorked = int.Parse(hoursWorkedTextBox1.Text);
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.");
}
```
38
What method is being used to display numeric values?
1. .ToString() method
39
How to show int myNumber = 123 to message box?
int myNumber = 123;
MessageBox.Show(myNumber.ToString());
*
Will get cannot convert from 'int' to 'string' when .ToString() isn't with myNumber in MessageBox
40
Use ToString() method to show number 12.3 with result 12.300
double x = 12.3;
MessageBox.Show(x.ToString(**"n3"**));
* Use "n3" inside .ToString()
41
Use ToString() method to show number 123 with result 123.00
int x = 123;
MessageBox.Show(x.ToString(**"f2"**));
* Use "f2" inside .ToString()
42
Use ToString() method to show number 123456.0 with result 1.235e+005
double x = 12.3;
MessageBox.Show(x.ToString(**"e3"**));
* Use "e3" inside .ToString()
43
Use ToString() method to show number -12.3 with result ($12.3)
double x = 12.3;
MessageBox.Show(x.ToString(**"C"**));
* Use "C" inside .ToString()
44
Use ToString() method to show number .234 with result 23.40%
double x = .234; // Same as 0.234
MessageBox.Show(x.ToString(**"P"**));
* Use "P" inside .ToString()
45
What is the difference between GroupBoxes and Panels
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
46
What property is similar to the Image property of a PictureBox?
1. BackgroundImage
47
List out 3 tabs that Windows Form Application provides for Colors
1. Web
2. System
3. Custom
48
How to create a access key for buttons? I want press Alt + E to close the page
1. Go to Text property and type &Exit
2. Then add code
```
public void exitButton_Click (object sender, EventArgs e )
{
this.Close();
}
```
49
List out 2 predefined constants that the Math Class provide
1. Math.PI
2. Math.E
50
How to use math class square root?
1. Math.Sqrt(x);
51
How to use math class power?
1. Math.Pow(x,y)
x = 2 , y = 3 will be 2³ = 8
52
What is an exception?
1. Is an unexpected error that happens while a program is running
* Will abruptly halt if an exception is not handled by the program
53
What code is used for exception handling?
try {}
catch {}
54
How to try parse text box input of age from string into int?
```
try
{
int age;
age = int.Parse(txtAge.Text);
}
catch
{
MessageBox.Show("Invalid Value Entered")
}
```
55
How to create a constant value of my birth year 2003?
const int myBirthYear = 2003;
* a constant variable represents a value that cannot be changed during the program's execution
56
How to declare variables as fields so that every method can use that value?
```
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
57
How to show message box with the requirement below
1. Title : Logout
2. Description : Are you sure ?
3. Icon : Question Mark
4. Button : With Ok and Cancel
```
MessageBox.Show("Are you sure?" , "Logout" , MessageBoxButtons.OkCancel, MessageBoxIcon.Question);
```
58
List out all 6 relational operators
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
59
Write a program to receive temperature from numeric up down with the conditions
1. >= 40 is Hot
2. < 40 and >= 10 is Ok
3. < 10 is Cold
```
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");
}
```
60
List out 3 logical operator
1. && - And
2. || - Or
3. ! - Not
61
Write a program to receive months from numeric up down with showing the correct month ( 1 - January )
```
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");
}
```
62
Write a program to compare if 2 name is the same using String.Compare
```
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
```
63
What is the boolean variable called when is being used inside if statement?
```
bool grandMaster = false;
if (grandMaster)
{
powerLevel += 500; //powerLevel = powerLevel +500;
}
if (!grandMaster)
{
powerLevel = 100;
}
```
1. Flags
64
Write a program to use int.TryParse to return age from textbox
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()**
65
What is input validation?
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 )
66
What is the difference between Radio Buttons and Check Boxes?
1. Radio buttons can only choose one from several possible choices, while Check Boxes can select multiple options
67
Write a program to check if the radio button male or female is pressed, then return text Male and Female
```
if ( rdrMale.Checked )
{
MessageBox.Show("Male");
}
else if ( rdrFemale.Checked )
{
MessageBox.Show("Female");
}
```
or
```
MessageBox.Show(rdrMale.Text);
```
68
What event is when the checked property changes?
1. CheckedChanged
69
Write a program to add items to list box (listBoxFruits) when the program is first loaded then print out the fruit when user had press the btnShowSelected
```
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();
```
70
Write a program to print Hello 5 times
```
for ( int i = 0 ; i < 5 ; i ++ )
{
MessageBox.Show("Hello")
}
```
71
How to show 1 to 100 using for loop?
```
for ( int i = 1 ; i <= 100 ; i++ )
{
MessageBox.Show(i.ToString());
}
```
72
How to show 100 to 1 using for loop?
```
for ( int i = 100 ; i <= 1 ; i-- )
{
MessageBox.Show(i.ToString());
}
```
73
List out 2 pretest loops
1. for loop
2. while loop
74
List out posttest loop
1. do-while loop
75
Write a program using while loop to show Hello 5 times
```
int i = 0 ;
while ( i < 5 ){
MessageBox.Show("Hello");
i++ ;
}
```
Omitting i ++ will be showing **Hello** Infinitely
76
Until Slide 16
