std::bind(callable, arg_list)

std::bind(callable, arg_list)

#include <iostream>
#include <string>
#include <algorithm>
#include <functional>   //std::bind(callable, arg_list)

using namespace std;
using namespace std::placeholders;

bool check_size(const string &s, string::size_type sz){
    return s.size() >= sz;
}
bool isShorter(char a, char b){
    return a < b;
}
ostream &print(ostream &os, char c, char s){
    return os << s << c;
}
int main(int argc, char* argv[]){
    string s = "hello";
    check_size(s, 6);
    //参数绑定
    auto check = bind(check_size, _1, 6);
    check(s);
    auto check2 = bind(check_size, _2, _1);
    check2(6,s);
    //
    sort(s.begin(), s.end(), isShorter);
    cout << s << endl;
    sort(s.begin(), s.end(), bind(isShorter,_2,_1));
    cout << s << endl;

    ostream &os = cout;
    for_each(s.begin(), s.end(),bind(print, ref(os), _1, ' '));//需要使用标准库的ref()进行绑定引用参数
    cout << endl;
    for_each(s.begin(),s.end(),[&os,s](char c) mutable {s=" "; os << s << c;});
    cout << endl;
    auto print2 = [&os,s](char c) mutable {s=" "; os << s << c;};
    for_each(s.begin(),s.end(),bind(print2 , _1));
    return 0;
}