what is meant by trailing space and what's the difference between it and a blank?

Question

What is meant by trailing space and what's the difference between it and a blank ? I saw an exercise where there is a note about trailing space.

I didn't see the problem on that because cin can ignore those spaces and catch only numbers ?

Answer 1

Trailing space is all whitespace located at the end of a line, without any other characters following it. This includes spaces (what you called a blank) as well as tabs \t, carriage returns \r, etc. There are 25 unicode characters that are considered whitespace, which are listed on Wikipedia.

Answer 2

what's the difference between [trailing space] and a blank?

A blank at the end of a line is a trailing space. A blank between characters (or words, or digits) is not a trailing space.

what is meant by trailing space?

Trailing space became a challenge for me for something I was trying to code. The challenge inspired me to create the following utility routines. For this particular effort, I defined "trailing space" as any "white space" at the end of a line. (Yes, I also created versions of this function for leading white space, and extra white space (more than 1 white space character in the middle of the line.)

const char* DTB::whitespaces = "\t\n\v\f\r ";
//                               0 1 2 3 4 5
// 0)tab, 1)newline, 2)vertical tab, 3)formfeed, 4)return, 5)space,


void DTB::trimTrailingWhiteSpace(std::string& s)
{
   do // poor man's try block
   {
      if(0 == s.size())  break;  // nothing to trim, not an error or warning

      // search from end of s until no char of 'whitespaces' is found
      size_t found = s.find_last_not_of(DTB::whitespaces);

      if(std::string::npos == found)  // none found, so s is all white space
      {
         s.erase(); // erase the 'whitespace' chars, make length 0
         break;
      }

      // found index to last not-whitespace-char
      size_t trailingWhitespacesStart = found + 1; // point to first of trailing whitespace chars
      if(trailingWhitespacesStart < s.size())      // s has some trailing white space
      {
         s.erase(trailingWhitespacesStart); // thru end of s
         break;
      }

   }while(0);

} // void trimTrailingWhiteSpace(std::string& s)