/*Tyler Taormina and Isabella Mon
 * CST 116
 * 
 * Project 2 
 */

#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

int GetData();
void DisplayMenu (int&);
void ProcessMenuChoice (int, int);
void IsPosNeg (int);
void IsOddEven (int);
void DisplayAdditionTable();
void DisplayMultiplicationTable();
void FindNumDigits(int);
void FindDigitAtPosition(int);

int main() {
    int User_Value = 0;
    int Menu_choice = 0;
    User_Value = GetData();
    DisplayMenu(Menu_choice);
    ProcessMenuChoice(Menu_choice, User_Value);


    return 0;
}


int GetData(){
    //receives input from user within negative million and positive million.
    int usr_data = 0;
    cout << "================================================================" << endl;
    cout <<  "Program Running..." << endl;
    cout << "================================================================\n\n\n" << endl;

    cout << "Please enter the number you would like to have tested: ";
    cin >> usr_data;

    if (usr_data < -1000000 || usr_data > 1000000 ){
        cout << "Sorry. The number you have entered is out of bounds. Please try again." << endl;
        GetData();
    }
    return usr_data;
}


void DisplayMenu(int& menu_choice) {
    //displays the menu of functions for the user to choose from

    cout << "1) Determine if the number is positive or negative.\n";
    cout << "2) Determine if the number is odd or even.\n";
    cout << "3) Determine the number of digits in the entered number.\n";
    cout << "4) Determine what digit is at a given position in the number.\n";
    cout << "5) Display Addition Table.\n";
    cout << "6) Display Multiplication Table.\n";
    cout << "7) Exit Program.\n\n";
    cout << "Enter: ";
    cin >> menu_choice;
    if (menu_choice > 7 || menu_choice < 1) {
        cout << "Invalid Entry. Please enter a  number from the options list provided.\n\n\n\n" << endl;
        DisplayMenu(menu_choice);
    }
}


void ProcessMenuChoice (int menu_choice, int usr_data) {
    int program_rerun = 0;
    switch(menu_choice){
        case 1: 
            IsPosNeg(usr_data);
            break;
        
        case 2: 
            IsOddEven(usr_data);
            break;

        case 3:
            FindNumDigits(usr_data);
            break;

        case 4:
            FindDigitAtPosition(usr_data);
            break;

        case 5:
            DisplayAdditionTable();
            break;

        case 6: 
            DisplayMultiplicationTable();
            break;

        case 7: 
            cout << "End program." << endl;
            break;

        default:
            break;
    }
    cout << "Press 1 and enter to rerun program. Enter any other number to close program: ";
    cin >> program_rerun;

    if (program_rerun == 1)
        main();
    
    else {
    cout << "================================================================" << endl;
    cout <<  "Program Closing..." << endl;
    cout << "================================================================\n\n\n" << endl;
}


    }
    

void IsPosNeg (int usr_data) {
    // checks whether the number entered is positive or negative. 
    // Displays appropriate message. 
    if (usr_data < 0) 
        cout << "The number is negative" << endl;
    else if (usr_data > 0)
        cout << "The number is positive." << endl;
    else
        cout << "The number is zero." << endl;

}


void IsOddEven(int usr_data) {
    // checks if the user enterd number is odd or even.
    // displays an appropriate message. 

    if ((usr_data % 2) == 0)
        cout << "The number is even." << endl;
    else 
        cout << "The number is odd." << endl;

}



void DisplayAdditionTable()
{
    int i, j, k;
    int intList1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int intList2[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

    cout << "ADDITION TABLE!\n" << endl;
    
    for (i = 0; i < 11; i++) {
        cout << setw(5) << left << intList1[i] << setw(5) << left;
    }
    cout << endl;

    for (k = 0; k < 10; k++) {
        cout << setw(5) << left << intList2[k];
        for (j = 1; j < 11; j++) {
            cout << setw(5) << left << intList1[j] + intList2[k];
        }
        cout << endl;
    }
    
    cout << endl;

}



void DisplayMultiplicationTable()
{
  int i, j, k;
    int intList1[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int intList2[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

    cout << "Multiplication Table!\n" << endl;
    
    for (i = 0; i < 11; i++) {
        cout << setw(5) << left << intList1[i] << setw(5) << left;
    }
    cout << endl;

    for (k = 0; k < 10; k++) {
        cout << setw(5) << left << intList2[k];
        for (j = 1; j < 11; j++) {
            cout << setw(5) << left << intList1[j] * intList2[k];
        }
        cout << endl;
    }
    
    cout << endl;
 
}


void FindNumDigits(int usr_data)
{
    int copy = usr_data;

    // the "length" of 0 is 1:
    int length = 1;

    // and for numbers greater than 0:
    if (copy > 0) {
        // we count how many times it can be divided by 10:
        // (how many times we can cut off the last digit until we end up with 0)
        for (length = 0; copy > 0; length++) {
            copy /= 10;
        }
    }

    // and that's our "length":
    cout << "The number of digits is: " <<  length << endl << endl; 
}


void FindDigitAtPosition(int usr_data) 

{
    int position = 0;
    int copy = usr_data;
    int copy_length = usr_data;
    int correct_pos;

    // the "length" of 0 is 1:
    int length = 1;

    // and for numbers greater than 0:
    if (copy_length > 0) {
        // we count how many times it can be divided by 10:
        // (how many times we can cut off the last digit until we end up with 0)
        for (length = 0; copy_length > 0; length++) {
            copy_length /= 10;
        }
    }

    cout << "Enter the position you would like to check: ";
    cin >> position;
    correct_pos = length - position;

    copy /= pow(10, correct_pos);
    copy = abs(copy % 10);

    cout << "The number at position " << position << " is: " << copy << endl;
}