Problem with shuffle vector of structures

[marfur]

I'm trying to shuffle the order of the people in my list but I can't get it to work.

struct Person
{
    string firstname;
    string lastname;
    string sign;
    float length;
};

int myrandom (int i) { return std::rand()%i;}

void randomize(vector<Person> persons)
{
    srand ( unsigned ( std::time(0) ) );
    
    // using built-in random generator:
    random_shuffle ( persons.begin(), persons.end() );
    
    // using myrandom:
    random_shuffle ( persons.begin(), persons.end(), myrandom);
    
    // print out content:
    for(auto& e : persons)
    {
        cout << left << e.sign;
        cout << right << setw(20) << e.firstname;
        cout << setw(20) << e.lastname;
        cout << right << setw(5) << e.length << endl;
    }
    
    return;
}

[2kaud]

srand() is usually only used once at the beginning of a program.

Any changes to the vector persons will be lost when the function exits as it is being passed by value and not by reference.

There's no need to do two shuffles - just use one. The example given for random_shuffle() was to show how it's used in both cases.

[marfur]

Thanks!