int array[3] = {3,1,5};
int largest = array[0];
int smallest = array[0];
for(int i = 1; i < 3; i++)
{
    if( array[i] > largest)
        largest = array[i];
    // now do similar for smallest
}

#include <iostream>
#include <algorithm>
 
int main()
{
  int a = 0;
  int b = 1;
  int c = 2;
 
  std::cout << "Low number: " << std::min(std::min(a, b), c) << '\n';
  std::cout << "High number: " << std::max(std::max(a, b), c) << '\n';
}

#include <algorithm>
#include <iostream>
using namespace std;
 
int main()
  {
  int numbers[] = { 12, -7, 42, 9 };
 
  cout << "largest  = " << max_element( numbers, numbers +4 ) << endl;
  cout << "smallest = " << min_element( numbers, numbers +4 ) << endl;
  }

#include <iostream>
 
template < typename T > T largest( T first, T second )
{  return first > second ? first : second ; }
 
 
template < typename T, typename... U > T largest( T first, U... rest )
{ return largest( first, largest( rest... ) ) ; }
 
int main()
{
   int n1=5, n2=7, n3=1 ; 
   std::cout << largest( n1, 4, n2 ) << '\n' ;
   std::cout << largest( n1, 78, 3, n2, 12, n3 ) << '\n' ;
}
 
// compile with: g++43 -Wall -std=c++0x -pedantic -Werror myfile.cc