How to get min or max element in a vector of structures in c++, based on some field in the structure?

Question

How to get min or max element in a vector of structures in c++, based on some field in the structure?

For example:

struct Size {
    int width, height;
}         


        

Answer 1

You can use std::min_element and std::max_element with a suitable functor:

bool cmp(const Size& lhs, const Size& rhs)
{
  return lhs.width < rhs.width;
}

then

auto min_it = std::min_element(sizes.begin(), sizes.end(), cmp);
auto max_it = std::max_element(sizes.begin(), sizes.end(), cmp);

In C++11 you can replace cmp with a lambda expression.

See also: std::minmax_element