FunC++

#include <iostream>
#include <vector>

using namespace std;

void printList(vector<int>);
void get_average(vector<int>);
void smallest_data(vector<int>);
void largest_data(vector<int>);
void show_menu();

int main(){

    vector<int> list {1,2,3,4};

    bool run = true;

    show_menu();
    while(run){
        char data {};
        cout << "\tChoose Any : ";
        cin >> data;
        data = tolower(data);
        switch(data){
            case 'p':
                printList(list);
                break;
            case 'a':
                cout << "Enter The Data : ";
                int number;
                cin >> number;
                list.push_back(number);
                cout << number << " Added\n";
                break;
            case 'm':
                get_average(list);
                break;
            case 's':
                smallest_data(list);
                break;
            case 'l':
                largest_data(list);
                break;
            case 'q':
                cout << "GoodBye" <<endl;
                run = false;
                break;
            default :
                cout << "Unknown Selection!! Please Try Again...." << endl;
                show_menu();
                break;
        }
    }
    return 0;
}

void show_menu(){
    cout << "P - Print Numbers\nA - Add Numbers\nM - Display Mean Of The Numbers\n" <<
    "S - Display The Smallest Number\nL - Display The Largest Number\n" <<
    "Q - Quit\n";
}

void printList(vector<int> my_list){
    if(my_list.size() == 0){
        cout << "[] - the list is empty" << endl;
        return;
    }
    cout << "[ ";
    for(auto int_data : my_list){
        cout << int_data <<" ";
    }
    cout << "]\n";
}

void get_average(vector<int> my_list){
    if(my_list.size() == 0){
        cout << "Unable To Calculate Mean - No Data" << endl;
        return;
    }

    int sum {0};
    for(auto int_data : my_list){
        sum += int_data;
    }
    cout << "Average = " << static_cast<double>(sum) / my_list.size() << endl;
}

void smallest_data(vector<int> my_list){
    if(my_list.size() == 0){
        cout << "Unable To Determine The Smallest Number - List Is Empty" << endl;
        return;
    }
    int temp {my_list.at(0)};
    for(auto int_data : my_list){
        if(int_data < temp)
            temp = int_data;
    }
    cout << "Smallest Number Is " << temp << endl;
}

void largest_data(vector<int> my_list){
    if(my_list.size() == 0){
        cout << "Unable To Determine The Largest Number - List Is Empty" << endl;
        return;
    }
    int temp {my_list.at(0)};
    for(auto int_data : my_list){
        if(int_data > temp)
            temp = int_data;
    }
    cout << "Largest Number Is " << temp << endl;
}