Removing punctuation from strings in C++98 and C++11

20121109.cpp

#include <string>
#include <iostream>
#include <cctype>
#include <iterator>
#include <algorithm>
#include <functional>
using namespace std;

int main()
{
    string before = "~$foo%(*bar@$|", after;

    cout << "before: " << before << endl;

    // C++98, remove all punctuation by copying
    remove_copy_if(before.begin(), before.end(), back_inserter(after), ptr_fun<int, int>(ispunct));

    cout << "after copy (C++98): " << after << endl;
    after.erase();

    // C++11, remove all punctuation by copying
    remove_copy_if(begin(before), end(before), back_inserter(after), [] (char c) { return ispunct(c); });

    cout << "after copy (C++11): " << after << endl;

    // C++98, remove in place using erase-remove idiom
    before.erase(remove_if(before.begin(), before.end(), ptr_fun<int, int>(ispunct)), before.end());
    cout << "in-place: " << before << endl;

    before = "...don't...";
    cout << "before: " << before << endl;

    // C++98, remove only leading and trailing punctuation but not interior
    // note: this is undefined behavior if the string contains all punctuation
    // (that can be fixed by assigning the two iterators to variables and checking that they aren't equal)    
    after = string(find_if(before.begin(), before.end(), not1(ptr_fun<int, int>(ispunct))),
                   find_if(before.rbegin(), before.rend(), not1(ptr_fun<int, int>(ispunct))).base());
    cout << "after: " << after << endl;
}

output.txt

$ g++ -Wall -Wextra -pedantic -std=c++11 -O2 20121109.cpp -o 20121109 && ./20121109
before: ~$foo%(*bar@$|
after copy (C++98): foobar
after copy (C++11): foobar
in-place: foobar
before: ...don't...
after: don't