Inbuilt .NET formatting tokens

gistfile1.cs

//
// In built formatters. These can have digit specifiers after them, such as {0:D5}
//

// Very similar to N (but no rounding), but with the currency symbol. See the section on regions.
Console.WriteLine("a) [C]urrency   - {0:C}", 1123.27);

// Integers only. The '5' sets the number of zeros to pad to the left.
Console.WriteLine("b) [D]ecimal    - {0:D5}", 1123);

// Fixed decimal places including rounding.
Console.WriteLine("c) [F]ixed      - {0:F3}", 1123.275);

// Scientific or decimal notation, whichever is shorter. Has a long set of rules in MSDN.
Console.WriteLine("d) [G]eneral    - {0:G}", 1123.275);

// Similar to fixed, but includes ',' thousand seperator and is rounded to 2 dp by default.
Console.WriteLine("e) [N]umber     - {0:N}", 1123.275);

// Percentage to 2 dp. So 0.99998 is 100%. The number is multiplied by 100 in order to be presented as a percentage
Console.WriteLine("f) [P]ercent    - {0:P}", 0.2345);

// This shows the percentage but as a whole number, rounded. The number is multiplied by 100 in order to be presented as a percentage
Console.WriteLine("g) [P]ercent    - {0:#%} ", 0.915);

double d1 = 1234.9998;
string rd = string.Format("{0:R}", d1);
double d2 = Double.Parse(rd);
Debug.Assert(d1 == d2);
Console.WriteLine("h) [R]ound trip  -  {0:R}", 0.9998);  // Allows you to parse the resulting string using Single.Parse() or Double.Parse()
Console.WriteLine("i) he[X]adecimal - 0x{0:X}", 255); // Integers only
Console.WriteLine("j) [E]xpontial   - {0:E}", 10000000);

Output:
a) [C]urrency   - £1,123.27
b) [D]ecimal    - 01123
c) [F]ixed      - 1123.275
d) [G]eneral    - 1123.275
e) [N]umber     - 1,123.28
f) [P]ercent    - 23.45 %
g) [P]ercent    - 92%
h) [R]ound trip  -  0.9998
i) he[X]adecimal - 0xFF
j) [E]xpontial   - 1.000000E+007