Sort based on multiple things in C++

Question

struct Record
{
    char Surname[20];
    char Initial;
    unsigned short int Gender; //0 = male | 1 = female
    unsigned short int Age;
};
Record X[100];
<         


        

Answer 1

It's better to implement comparator like this:

bool CompareRecords(const Record& a, const Record& b)
{
    if (a.Age < b.Age)
        return true;
    else if (a.Age > b.Age)
        return false;

    if (a.Gender < b.Gender)
        return true;
    else if (a.Gender > b.Gender)
        return false;

    if (strcmp(a.Surname, b.Surname) < 0)
        return true;

    return false;
}

This allows you to easy use of std::sort algorithm. Sorting itself will look like this:

std::sort(X, X + 100, &CompareRecords);

EDIT

You may even want to implement operator < for this structure -- in that case you can normally compare two objects of Record structure with operator <. And then you don't need to add the third parameter to std::sort. And well, with that and implemented operator == you can make all possible comparizons. :)