#include <iostream>
#include <fstream>

using namespace std;

bool averageFromFile(const string& name, double &average){
    ifstream inputFile;
    inputFile.open(name);
    if (inputFile){

        double number;
        double sum = 0;
        int count = 1;

        //Check to see if empty
        if(inputFile >> number){
            sum = sum + number;

            while(inputFile >> number){
                sum = sum + number;
                count++;
            }

            average = sum / count;
        }else{
            return false;
        }

        inputFile.close();
        return true;
    }else{
        return false;
    }
}

int main() {

    char menu_choice = 'K';
    string filename;

        do{
            cout << "Choose: L->Find lowest value, H->Find highest value, A->Find average, Q->Quit: ";
            cin >> menu_choice;

            //Validate input
            while(menu_choice != 'L' && menu_choice != 'H' && menu_choice != 'A' && menu_choice != 'Q'){
                cout << "Choose: L->Find lowest value, H->Find highest value, A->Find average, Q->Quit: ";
                cin >> menu_choice;
            }

            if (menu_choice == 'Q'){
                break;
            }


            double number = 0;
            double lowest;
            double highest;
            double average = 0;


                if(menu_choice == 'L'){

                    cout << "Enter input file name: ";
                    cin >> filename;

                    ifstream inputFile;
                    inputFile.open(filename);

                    if(inputFile) {

                        //Get the first value
                        inputFile >> number;

                        //Find the lowest value
                        lowest = number;
                        while(inputFile >> number){
                            if(number < lowest){
                                lowest = number;
                            }
                        }
                        cout << "Lowest value is " << lowest;
                    }else{
                        cout << "File empty or could not open file" << endl;
                    }
                    inputFile.close();
                }else if(menu_choice == 'H'){

                    cout << "Enter input file name: ";
                    cin >> filename;

                    ifstream inputFile;
                    inputFile.open(filename);

                    if(inputFile) {

                        //Find the highest value
                        highest = number;
                        while(inputFile >> number){
                            if (number > highest){
                                highest = number;
                            }
                        }
                        cout << "Highest value is " << highest;
                    }else{
                        cout << "File empty or could not open file" << endl;
                    }
                    inputFile.close();
                }

            if(menu_choice == 'A'){

                cout << "Enter input file name: ";
                cin >> filename;

                //Find average
                bool foundAverage = averageFromFile(filename, average);
                if(foundAverage){
                    cout << "Average value is " << average;
                }
            }

            cout << endl;
        }while(menu_choice != 'Q');
        cout << "Exiting" << endl;


    return 0;
}