The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference
by Nicolai M. Josuttis, Addison-Wesley, 1999
© Copyright Nicolai M. Josuttis 1999
#include <iostream>
#include <string>
#include <algorithm>
#include <iterator>
#include <locale>
using namespace std;
class bothWhiteSpaces {
private:
const locale& loc; // locale
public:
/* constructor
* - save the locale object
*/
bothWhiteSpaces (const locale& l) : loc(l) {
}
/* function call
* - returns whether both characters are whitespaces
*/
bool operator() (char elem1, char elem2) {
return isspace(elem1,loc) && isspace(elem2,loc);
}
};
int main()
{
string contents;
// don't skip leading whitespaces
cin.unsetf (ios::skipws);
// read all characters while compressing whitespaces
unique_copy(istream_iterator<char>(cin), // beginning of source
istream_iterator<char>(), // end of source
back_inserter(contents), // destination
bothWhiteSpaces(cin.getloc())); // criterion for removing
// process contents
// - here: write it to the standard output
cout << contents;
}