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

int main()
{
    std::vector<double> vec;
    for(double x{0.0}; x < 10.0 + 0.5; x += 1.0) vec.push_back(x);
    auto it = std::lower_bound( vec.begin(), vec.end(), 5.5 );
    if( it != vec.end() ) 
    	std::cout << "found:" << *it << std::endl;
    
}