Question

So I hava an unsorted array of 30 ints like 340, 6401 1280, and so on random numbers. I have int x which was cined by user. I need to find which value in array is nearest down (lower, smaller,less) to that x value. How to do such thing?

Answer 1

You could use std::max_element() with a custom comparison operator:

struct limited_cmp {
   int limit;
   limited_cmp(int a_limit) : limit(a_limit) {
   }
   bool operator()(int left, int right) const {
      if (left <= limit && limit < right) {
         return false;
      }
      return (left < right);
   }
};

int main() {
   std::vector<int> numbers = ...;
   std::cout << "nearest is "
         << *std::max_element(numbers.begin(), numbers.end(), limited_cmp(5))
         << std::endl;   
}