Bjarne Stroustrup “Programming Principles and Practice Using C++” Chapter 4 Drill 6
Using std_lib_facilities.h by Bjarne Stroustrup.

// Philipp Siedler
// Bjarne Stroustrup's PP
// Chapter 4 Drill 6
#include "std_lib_facilities.h"
int main()
{
cout << "type in doubles to be compared or a '|' to terminate the program:\n";
vector<double> numbers;
double x;
while (cin >> x)
{
numbers.push_back(x);
cout << "you entered: " << x << "\n";
sort(numbers);
if (x == numbers[0]){
cout << "the smallest so far is: " << x << "\n";
}
if (x == numbers[numbers.size() - 1]){
cout << "the largest so far is: " << x << "\n";
}
cout << "\n";
}
}

Output:
type in doubles to be compared or a '|' to terminate the program:
2.3
you entered: 2.3
the smallest so far is: 2.3
the largest so far is: 2.3
2.1
you entered: 2.1
the smallest so far is: 2.1
5.6
you entered: 5.6
the largest so far is: 5.6