Not easy understand. try make test.
It could be better explained but it's not so difficult either
The general sintax is:
Value:MinimumWidth[:Decimals]and the value will be right-justified in the field so, for example:
MyString := 'Just a String';
MyFloat := 1.563;
Writeln('"', MyString:20, '"');
Writeln('"', MyFloat:20:4, '"');
will result in:
" Just a String"
" 1.5630"
If the value to print is larger than the minimum width (for example, if
MyString had been 30 characters long) then the minimum width is ignored and the value is printed in full.
That's basically all there is to it.