std::bind

bind1st和bind2nd

#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
using namespace std; 

typedef struct Print{
    void operator()(int a) {
        cout <<a<<"--";
    }
}myPrint;

// binary_function<参数1，参数2，返回值类型>
struct myPrint2:public binary_function<int,int,void>{
    void operator()(int a, int b)const {
        cout <<a*b<<"--";
    }
};

void fun() {
    vector<int>v1{1,2,3,4};
    for_each(v1.begin(), v1.end(), myPrint());
    cout <<endl;
    for_each(v1.begin(), v1.end(), bind2nd(myPrint2(),10));
    cout <<endl;
    for_each(v1.begin(), v1.end(), bind1st(myPrint2(),10));

}

int main() {
    fun();
    return 0;
}

image.png

bind

#include <iostream>
#include <functional>
using namespace std;
 
int fun(int a, char c, float f)
{
    cout << a << endl;
    cout << c << endl;
    cout << f << endl;
 
    return a;
}
 
int main()
{ 
    auto bindFunc3 = bind(fun, std::placeholders::_2, std::placeholders::_3, std::placeholders::_1);
    bindFunc3(100.1, 30, 'C');
 
    return 0;
}

image.png