string by value

#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int func(std::string str){
    cout << "in bef: "<< str << " : " << str.size() << endl;
    str.clear();
    cout << "in aft: "<< str << " : " << str.size() << endl;
    return 0;
}

int main()
{
   std::string str("qwertyuiop");
   
   cout << "bef:" << str << " : " << str.size() << " : " << sizeof(str) << endl;  
   func(str);
   cout << "aft:" << str << " : " << str.size() << endl;    
   return 0;
}