g ++ string remove_if错误

Question

这是代码:

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main()
{
    string word="";
    getline(cin,word);
    word.erase(remove_if(word.begin(), word.end(), isspace), word.end()); 
    word.erase(remove_if(word.begin(), word.end(), ispunct), word.end()); 
    word.erase(remove_if(word.begin(), word.end(), isdigit), word.end());
}

在VS 2010中编译时,它运行得非常好.用G ++编译它说:

hw4pr3.cpp: In function `int main()':
hw4pr3.cpp:20: error: no matching function for call to `remove_if(__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, <unknown type>)'
hw4pr3.cpp:21: error: no matching function for call to `remove_if(__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, <unknown type>)'
hw4pr3.cpp:22: error: no matching function for call to `remove_if(__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, <unknown type>)'

Answer 1

添加::到开头isspace,ispunct并且isdigit,因为它们有重载,编译器无法决定使用哪个:

word.erase(remove_if(word.begin(), word.end(), ::isspace), word.end()); 
word.erase(remove_if(word.begin(), word.end(), ::ispunct), word.end()); 
word.erase(remove_if(word.begin(), word.end(), ::isdigit), word.end());