Unit 1 Jan 2017 Question 4 preparation

What does if(userid.text!= "") do?

• Check to see if "" is the text box

• Check to see if the text box is empty

• Check to see if the text box exists

• Check to see if there is text in the text box

Answer explanation

The condition if(userid.text != "") checks if the text box is not empty. If it contains any text, it evaluates to true, confirming that there is text in the text box.

What does if(userid.text!= "" && ridename.text!="") do?

• Check to see if "" is in the userid and ridename text box

• Check to see if the userid and ridename text boxes are empty

• Check to see if the userid and ridename text boxes exists

• Check to see if there is text in the userid and ridename text boxes

Answer explanation

The condition checks if both userid and ridename text boxes are not empty. If they contain text, the condition evaluates to true, indicating that valid input is present.

What does File.ReadAllLines(@"./log.txt") do?

• Reads the first line of text from the log.txt file

• Reads all the lines from the log.txt file

• Writes @ to the log.txt file

• Clears the log.txt file

Answer explanation

File.ReadAllLines("./log.txt") reads all lines from the specified log.txt file and returns them as an array of strings. This makes the correct answer 'Reads all the lines from the log.txt file'.

What does File.ReadAllLines(@"./log.txt").Length return?

• The number of characters in the text file

• The size of the text file

• The number of lines in the text file

• How many @ characters appear in the text file

Answer explanation

File.ReadAllLines reads all lines from a file and returns them as an array. The Length property of this array indicates the number of lines in the text file, making 'The number of lines in the text file' the correct answer.

What does adding .ToString do to File.ReadAllLines(@"./log.txt").Length so it becomes File.ReadAllLines(@"./log.txt").Length.ToString()

• Changes the integer length to a string

• Changes the string length to an integer

• Changes the array to a string

• Changes the file to a string

Answer explanation

Adding .ToString converts the integer result of File.ReadAllLines(@"./log.txt").Length into a string representation. This is important for scenarios where a string format is required, making the correct choice: 'Changes the integer length to a string'.

What does the instruction File.AppendAllText( filename, array) do?

• Overwrites the text in the text file with the text in the array

• Deletes the textfile

• Adds text from the array to the existing text in the text file

• Creates a new array

Answer explanation

File.AppendAllText appends the text from the array to the existing content of the specified text file, rather than overwriting it. This means any previous text remains intact while new text is added.

What does the Parse command do, eg int.Parse()?

• Changes the given text to a different data type

• Adds the text to an array

• Adds the text to a file

• Creates a new text file

Answer explanation

The Parse command, such as int.Parse(), converts a string representation of a number into an integer data type. This is why the correct answer is 'Changes the given text to a different data type'.

What does TimeSpan.Parse(starttime.Text) do?

• Converts the text in the starttime text box to a string

• Deletes the text in the starttime text

• Converts the text in the starttime text box to a time

• Adds the text from starttime text box to an array

Answer explanation

TimeSpan.Parse(starttime.Text) converts the string input from the starttime text box into a TimeSpan object, representing a time interval. This makes the correct choice 'Converts the text in the starttime text box to a time'.

What does time_taken=end_time - start_time do?

• Updates time_taken to a string

• Stores the time_taken in an array

• Calculates the difference between start and end time and store this as a time.

• Compares the time_taken to the target_time

Answer explanation

The expression time_taken=end_time - start_time calculates the duration between the two time points, effectively measuring how long an operation took, and stores this value in the variable time_taken.

What does this.Close() do?

• Closes the current form

• Deletes the text box

• Refreshes the form

• Shuts the application down

Answer explanation

this.Close() is a method used in programming to close the current form or window in a user interface. Therefore, the correct answer is that it closes the current form.