Нахождение минимального / максимального / среднего значения последовательности в переполнении стека

Я создаю программу, которая имитирует заполнение резервуара. Пока все идет хорошо, за исключением последней вещи, которую я хочу сделать, — это получить максимальное, минимальное и среднее количество лет, необходимое для заполнения резервуара. Я хочу сделать это без использования массивов. Я думаю, что я близко, но я должен упустить что-то простое. Простите, я только учусь C ++.

#include <iostream>
#include <cstdlib>
#include <cmath>
#include <string>
#include <ctime>

using namespace std;int main ()
{

string operation;
do{
cout << "Using the letters 's', or 'q', please indicate if you would like to run a simulation, or quit the program: " << endl;
cin >> operation;
} while (operation != "s" && operation != "q");
string reservoir_name; // Creating variables for reservoir
double reservoir_capacity;
double outflow;
double inflow_min;
double inflow_max;

if (operation == "q")
{
cout << endl;
cout << "This was a triumph . . ." << endl;
cout << "I'm making a note here: huge success!" << endl;
system ("pause");
return 0;
}

while (operation == "s")
{

string reservoir_name; // Creating variables
double reservoir_capacity;

double inflow_min = 0;
double inflow_max = 0;
double inflow_average = inflow_min + inflow_max;
double inflow_difference = inflow_max - inflow_min;
double inflow_threshold = .9 * inflow_average/2; // Math for acceptable flow threshold.cout << "What is the name of the reservoir?" << endl;
cin.ignore ();
getline (cin,reservoir_name); // Grab whole string for reservoir name.
cout << "What is the capacity of the reservoir in MAF (Millions of Acre Feet)?" << endl;
cin >> reservoir_capacity;
cout << "What is the minimum inflow?" << endl;
cin >> inflow_min;
cout << "What is the maximum inflow?" << endl;
cin >> inflow_max;
cout << "What is the required outflow?" << endl;
cin >> outflow;
cout << endl;
inflow_average = inflow_min + inflow_max;
inflow_threshold = .9 * inflow_average/2; // Calculate threshold for too much outflow.
cin.ignore ();

if (outflow > inflow_threshold) // Check for unacceptable outflow levels.
{
cout << "Warning! The outflow is over 90% of the average inflow. Simulation aborted. Returning to main menu." << endl << endl;
}
else
{
const int number_simulations = 10;
cout << endl;
cout << "Reservoir name: " << reservoir_name << endl;
cout << "Capacity of reservoir in MAF: " << reservoir_capacity << endl;
cout << "Maximum inflow in MAF: " << inflow_max << endl;
cout << "Minimum inflow in MAF: " << inflow_min << endl;
cout << "Required outflow in MAF: " << outflow << endl << endl;

cout << "Running simulation . . ." << endl << endl;
srand (time(0));
const int sentinel = -1;
int minimum = sentinel;
int maximum = sentinel;
int years_total;
for (int i = 1; i <= number_simulations; i++) // Loop should run the filling simulation 10 times.
{

int years = 0;
double fill_level = 0;
for (years; fill_level < reservoir_capacity; years++ ) // Loop should simulate filling reservoir using random inflow values between inflow_min and inflow_max.
{

double r = rand() * 1.0 / RAND_MAX;
double x = inflow_min + (inflow_max - inflow_min) * r;// SHOULD be between minimum inflow and maximum inflow.
// cout << "Random Number x :" << x << endl; WAS USED TO CHECK IF RANDOM NUMBER WAS CHANGING
fill_level = fill_level + x - outflow;
if (fill_level < 0)
{
fill_level = 0; // Prevent fill level from going negative.
}
//cout << "Fill level is " << fill_level << endl; TO CHECK THE CHANGE IN FILL LEVEL PER ITERATION
if (minimum == sentinel || years < minimum) // Trying to set up the method for retrieving minimum value here. Currently returning as 0.
{
minimum = years;
}
if (maximum == sentinel || years > maximum) // Trying to set up the method for retrieving maximum value here. Currently returning as 1 less than the actual maximum.
{
maximum = years;
}
}   // Simulate the change of water level.

cout << "Simulation " << i << ": The reservoir took " << years << " years to fill." << endl;

}

cout << "The minimum number of years needed to fill: " << minimum << endl;
cout << "The maximum number of years needed to fill: " << maximum << endl;
cout << "The average number of years needed to fill: " << years_total / 10 << endl; // Take the running total of years over 10 simulations and divide by 10. Currently returning as 0.
}
cout << endl;
cout << "What would you like to do now?" << endl << endl; // Saving for later. The menu re-prompt message and code.
cout << "Using the letters 's', or 'q', please indicate if you would like to run a simulation or quit the program: " << endl;
cin >> operation;
if (operation == "q")
{
cout << endl;
cout << "This was a triumph . . ." << endl;
cout << "I'm making a note here: huge success!" << endl;
system ("pause");
return 0;
}
}system ("pause");
return 0;
}