Format specifiers for numbers and dates in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the format specifier "C" do when formatting numbers in C#?

The "C" specifier formats a number as currency, adding the currency symbol and two decimal places by default.

beginner

How do you format a DateTime to show only the year and month in C#?

Use the format specifier "yyyy-MM" with DateTime.ToString(), which shows the full year and two-digit month.

intermediate

What is the difference between "D" and "d" format specifiers for dates in C#?

"D" shows the long date pattern (e.g., "Monday, June 5, 2023"), while "d" shows the short date pattern (e.g., "6/5/2023").

beginner

How does the "N" format specifier format numbers in C#?

"N" formats numbers with thousands separators and two decimal places by default (e.g., "1,234.56").

beginner

What does the format specifier "F" do when formatting numbers?

"F" formats a number as a fixed-point number with a default of two decimal places (e.g., "1234.56"). You can specify decimals like "F3" for three decimals.

Which format specifier would you use to display a number as currency in C#?

A "F"

B "N"

C "D"

D "C"

The "C" specifier formats numbers as currency, adding the currency symbol and decimals.

What does the "d" format specifier show when formatting a DateTime?

A Short date pattern (e.g., 6/5/2023)

B Long date pattern (e.g., Monday, June 5, 2023)

C Time only

D Full date and time

"d" shows the short date pattern, which is a concise date format.

How would you format a number with thousands separators and two decimals in C#?

A "C"

B "F"

C "N"

D "P"

"N" adds thousands separators and formats with two decimals by default.

Which format specifier shows the full year and month in a DateTime string?

A "yyyy-MM"

B "d"

C "D"

D "F"

Using "yyyy-MM" custom format shows the full year and two-digit month.

What does the "F3" format specifier do when formatting a number?

A Formats as currency with 3 decimals

B Formats as fixed-point with 3 decimals

C Formats as number with thousands separators

D Formats as percentage with 3 decimals

"F3" formats a number as fixed-point with exactly 3 decimal places.

Explain how to format a number as currency and as a fixed-point number in C#.

Think about how money and precise decimals look.

Describe the difference between the "D" and "d" date format specifiers in C#.

One is detailed, the other is brief.