Delphi Date and String Manipulation

What function in Delphi is used to concatenate strings?

• Join

• Append

• Merge

• Concat

Answer explanation

In Delphi, the function used to concatenate strings is 'Concat'. It combines multiple strings into one, making it the correct choice among the options provided.

Which function formats a date into a string representation in Delphi?

• ParseDateTime

• StringToDate

• FormatDateTime

• DateToString

Answer explanation

The function FormatDateTime in Delphi is specifically designed to format a date into a string representation, making it the correct choice. The other options serve different purposes related to date handling.

How can you add days to a date variable in Delphi?

• Use the '+' operator to add days to a date variable.

• Use the '-' operator to subtract days from a date variable.

• Convert the date to a string before adding days.

• Call a function to multiply the date by a number of days.

Answer explanation

In Delphi, you can add days to a date variable using the '+' operator. This allows for straightforward date arithmetic, making it easy to manipulate date values directly.

What function converts a string to a TDateTime variable in Delphi?

• ConvertStringToDate

• DateTimeFromString

• StringToDate

• StrToDateTime

Answer explanation

The function StrToDateTime is used in Delphi to convert a string representation of a date and time into a TDateTime variable. It correctly parses the string format and returns the corresponding TDateTime value.

Which function retrieves the current date in Delphi?

• Date

• Now

• GetDate

• CurrentTime

Answer explanation

The correct function to retrieve the current date in Delphi is 'Date'. It returns the current system date without the time component, while 'Now' includes both date and time.

What is the purpose of the FormatDateTime function in Delphi?

• To format date and time values into a string representation.

• To perform mathematical operations on date and time values.

• To retrieve the current date and time from the system.

• To convert strings into date and time values.

Answer explanation

The FormatDateTime function in Delphi is specifically designed to format date and time values into a string representation, making it easier to display or manipulate these values in a user-friendly format.

How do you subtract one date from another in Delphi?

• Difference := Date1 + Date2;

• Difference := Date1 - Date2;

• Difference := Date1 * Date2;

• Difference := Date1 / Date2;

Answer explanation

To subtract one date from another in Delphi, you use the '-' operator. Thus, the correct choice is 'Difference := Date1 - Date2;', which calculates the difference between the two dates.

What function would you use to get the current time in Delphi?

• CurrentTime

• GetTime

• TimeNow

• Now

Answer explanation

In Delphi, the function 'Now' returns the current date and time. Other options like 'CurrentTime', 'GetTime', and 'TimeNow' are not standard functions for retrieving the current time.

How can you convert a TDateTime variable back to a string in Delphi?

• DateToStr(yourTDateTimeVariable)

• DateTimeToStr(yourTDateTimeVariable)

• FormatDateTime(yourTDateTimeVariable)

• StrToDateTime(yourStringVariable)

Answer explanation

The correct choice is DateTimeToStr(yourTDateTimeVariable), which converts a TDateTime variable to a string representation. DateToStr is for date only, while FormatDateTime requires a format string. StrToDateTime converts a string to TDateTime.

What is the function used to extract the year from a date in Delphi?

• GetYear

• YearOf

• ExtractYear

• DateToYear

Answer explanation

The function used to extract the year from a date in Delphi is 'YearOf'. It takes a date value and returns the corresponding year as an integer, making it the correct choice among the options provided.