How can I sort a vector in C++ using STL?

How can I sort a vector in C++ using STL?

You can use the std::sort function from the <algorithm> header to sort a vector in C++. Here's a simple example:

#include <iostream>
#include <vector>
#include <algorithm>

int main() {
    std::vector<int> vec = {5, 2, 8, 1, 3};
    std::sort(vec.begin(), vec.end());
    for (int num : vec) {
        std::cout << num << " ";
    }
    return 0;
}

What if I want to sort it in descending order?

You can use the std::greater<int>() as a third argument in std::sort. Here's how:

std::sort(vec.begin(), vec.end(), std::greater<int>());

Can I sort a vector of custom objects?

Yes, you can sort a vector of custom objects by providing a custom comparison function or a lambda expression. For example:

struct Person {
    std::string name;
    int age;
};

std::vector<Person> people = {{"Alice", 30}, {"Bob", 25}};
std::sort(people.begin(), people.end(), [](const Person &a, const Person &b) {
    return a.age < b.age;
});

What header files do I need to include?

You need to include <vector> for the vector and <algorithm> for the std::sort function. If you're using custom objects, include <string> as well.