Remove spaces from a string in C++

Question

I am currently learning C++. I am trying to code a method to remove white spaces form a string and return the string with no spaces This is my code:

string removeSpaces(string input)
{
  int length = input.length();
  for (int i = 0; i < length; i++) {
     if(input[i] == ' ')
        input.erase(i, 1);
  }
  return input
}

But this has a bug as it won't remove double or triple white spaces. I found this on the net

s.erase(remove(s.begin(),s.end(),' '),s.end());

but apparently this is returning an iterator (if I understand well) Is there any way to convert the iterator back to my string input? Most important is this the right approach?

Answer 1

std::string::erase returns an iterator, but you don't have to use it. Your original string is modified.

string removeSpaces(string input)
{
  input.erase(std::remove(input.begin(),input.end(),' '),input.end());
  return input;
}

Answer 2

std::remove_if along with erase would be much easier (see it live):

input.erase(remove_if(input.begin(), input.end(), isspace),input.end());

using std::isspace had the advantage it will capture all types of white space.