simple min/max

[skyline01]

I have a question about finding the maximum and minimum elements in a list. (The list in question will be quite small -- only 2 elements -- so I am hoping for an efficient solution to all of this.) Is there a way to do this simply and efficiently? I am making my switch over from Matlab and Mathematica to C++, so I was expecting to find a pre-defined function for this. I was surprised to learn that this function isn't part of math.h. Thanks!

[Peter87]

by list do you mean std::list or an array? If you mean std::list you should not expect to find it in math.h (or cmath) because that is an old C header and C didn't have std::list. You can use std::max_element and std::min_element to get the max and min value of the list.

#include <iostream>
#include <list>
#include <algorithm>

int main()
{
	std::list<int> l;
	l.push_back(2);
	l.push_back(8);
	l.push_back(132);
	l.push_back(-2);
	l.push_back(53);
	l.push_back(24);
	
	std::list<int>::iterator max = std::max_element(l.begin(), l.end());
	std::list<int>::iterator min = std::min_element(l.begin(), l.end());
	
	std::cout << "Max: " << *max << std::endl;
	std::cout << "Min: " << *min << std::endl;
}

[skyline01]

Sorry for the ambiguity. I meant an array.

[tfityo]

The same code is valid for vectors:

        vector<int> l;
         // fill the vector
	std::vector<int>::iterator max = std::max_element(l.begin(), l.end());
	std::vector<int>::iterator min = std::min_element(l.begin(), l.end());

Read also this http://www.cplusplus.com/reference/algorithm/max_element/

[Peter87]

pointers can work as iterators so max_element and min_element works for arrays too.

#include <iostream>
#include <algorithm>

int main()
{
	int arr[] = {2, 8, 132, -2, 53, 24};
	
	int* max = std::max_element(arr, arr + 6);
	int* min = std::min_element(arr, arr + 6);
	
	std::cout << "Max: " << *max << std::endl;
	std::cout << "Min: " << *min << std::endl;
}

[skyline01]

Thank you for the responses. This definitely helps.