set-empty

////////////////////////////////////////
//      2018/04/28 13:45:21
//      set-empty

// ture if set is empty
#include <iostream>
#include <set>

using namespace std;

void print(set<int, less<int>>& s){
    set<int, less<int>>::iterator it;
    for (it = s.begin(); it != s.end(); it++){
        cout << *it << " ";
    }
    cout << endl;
}
//======================
int main(){
    int ary[] = { 1, 2, 3, 2, 3, 4, 8, 2, 5, 6 };
    set<int, less<int>> s;

    s.insert(ary, ary + 10);
    print(s);

    cout << "set is ";
    s.empty() ? cout << "" : cout << "not ";
    cout << "empty." << endl;

    s.clear();

    cout << "set is ";
    s.empty() ? cout << " " : cout << "not";
    cout << "empty." << endl;

    return 0;
}

/*
OUTPUT:
    1 2 3 4 5 6 8
    set is not empty.
    set is  empty.
*/ 
原文地址:https://www.cnblogs.com/laohaozi/p/12537916.html