For example, if you have a list of voltages and you want to concatenate them all in a string that is delimited with a comma and a space ", " you could write something like this...
voltage_string << " "
_for i_volt _over voltages.fast_elements()
voltage_string +<< i_volt+", "
voltage_string << voltage_string.subseq(1,voltage_string.size-2)+"."
... or you could use the core
write_string_with_separator()procedure and write equivalent code like this...
voltage_string << write(" ",
I like the latter approach because it is more concise and it very clearly indicates what you are trying to do... write a string with delimiter.