How to remove whitespace in a sentence using remove command in C++?

I get a file as input and I read the first line like this (quotes mark the begin and end, but are not in the file):

"      1,     2.0,     3.0,     4.0                         "

When I use the remove command like this:

    astring = line;
    cout << endl << "Bef开发者_运维问答ore trim: " << line << endl;
    remove(astring.begin(), astring.end(), ' ');
    cout << endl << "After trim: " << astring << endl;

I got the output as:

1,2.0,3.0,4.02.0,    3.0,     4.0

I need the output as 1,2.0,3.0,4.0 only. What is the problem here?

std::remove just moves all of the non-removed elements forward in the sequence; you then need to truncate the underlying container, using erase:

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

This is called the erase-remove idiom. remove cannot truncate the underlying container itself because it doesn't have a reference to the container; it only has iterators to elements in the container.

James was correct in his answer and it saved me a lot of work. td::remove just moves all of the non-removed elements forward in the sequence; you then need to truncate the underlying container, using erase:

std.erase(std::remove(s.begin(), s.end(), ' '), s.end()); This is called the erase-remove idiom. remove cannot truncate the underlying container itself because it doesn't have a reference to the container; it only has iterators to elements in the container.