Concatenates a specified separator string between each element of a specified object array, yielding a single concatenated string.
Parameters
separator
A string separator.
values
An array of Object.
Returns
A string consisting of the elements of value interspersed with the separator string.
Remarks
For example if separator is ", " and the elements of value are "red", "blue", "green", and "yellow", Join(separator, value) returns "red, blue, green, yellow".
stream << operator is called on each object to generate the content.