What is the use of {0} in c# console.writeline?

Question

What is the use of {0} in the console.writeline("Length: {0]"); in c#. and why are we using it?

Answer 1

{0} is a format string parameter.

For example,

    Console.WriteLine("Hello {0}!", "World")

will output

    Hello World!

to the Console.

Note, that in your example, the code reads {0] instead of {0} and you are also missing an argument for the intended parameter. In my example, the string "World" is the argument for the {0} format parameter).

A good, introductory source of information for this is available at: http://www.blackwasp.co.uk/StringFormat.aspx . It is worth noting that

    Console.WriteLine("Hello {0}!", "World");

is equivalent to

    Console.WriteLine(string.Format("Hello {0}!", "World"));