Trim whitespace from strings

It is common for input from users to include extraneous whitespace at one or both ends of a string. This can be problematic, so we often need to remove it. In this recipe, we'll use the string class methods, find_first_not_of() and find_last_not_of(), to trim whitespace from the ends of a string.

How to do it…

The string class includes methods for finding elements that are, or are not, included in a list of characters. We'll use these methods to trim string:

• We start by defining string with input from a hypothetical ten-thumbed user:

  int main() {
      string s{" \t  ten-thumbed input   \t   \n \t "};
      cout << format("[{}]\n", s);
      ...

Our input has a few extra tab \t and newline \n characters before and after the content. We print it with surrounding brackets to show the whitespace:

[...