Digit.cpp - Get a Digit from a Specific Position

/**
 * [Digit.cpp]
 * A program that returns the digit from a specified position in a provided integer.
 *
 * (c) Damion 'Phr0z3n.dev' Tapper, 2016
 * Email: [email protected]
 */
#include <iostream>
#include <sstream>


/**
 * Function Prototypes:
 */
int digit(int, int);
std::string IntToString(int);
int * StringToIntArray(std::string);
std::string ReverseString(std::string);


/**
 *
 */
using std::cout;
using std::cin;
using std::endl;


/**
 * The main() function:
 *
 * The program entry point.
 */
int main(void)
{
    int number;
    int position;

    /**
     * Input:
     */
    cout << "Enter number:" << endl;
    cin >> number;

    cout << endl << "Enter position:" << endl;
    cin >> position;

    cout << endl;

    /**
     * Output:
     */
    cout << digit(number, position) << endl;

    return 0;
}


/**
 * The digit function:
 *
 * A function that returns the digit from a specified position in a provided integer.
 */
int digit(int num, int k)
{
        /**
         * Error check:
         */
        if(num < 0)
        {
            cout << "Error!  Positive integers only!" << endl;

            exit(1);
        }


    /**
     * Convert the number to string:
     */
    std::string StringBuff = IntToString(num);

        /**
         * Error check:
         */
        if(k < 0 || k >= StringBuff.length())
        {
            cout << "Error!  Position out of range!" << endl;

            exit(1);
        }


    /**
     * Reverse the string:
     */
    StringBuff = ReverseString(StringBuff);


    /**
     * Convert the string to an integer array:
     */
    int *IntArray = StringToIntArray(StringBuff);


    /**
     * Return the appropriate digit:
     */
    return IntArray[k];
}


/**
 * The IntToString() function:
 *
 * A function that converts a given integer value to a string, and returns the conversion.
 */
std::string IntToString(int Number)
{
    std::ostringstream  converter;                                      // Converts from number to string.


    /**
     * Perform the conversion:
     */
    converter << Number;


    /**
     * Return the result:
     */
    return converter.str();
}


/**
 * The StringToIntArray() function:
 *
 * A function that receives a string and returns and integer array representation of it.
 */
int * StringToIntArray(std::string StringBuff)
{
    int *IntArray = new int[StringBuff.length()];


        /**
         * Perform string conversion:
         */
        for(int i = 0; i < StringBuff.length(); i++)
        {
            switch(StringBuff.data()[i])
            {
                case '0':
                    IntArray[i] = 0;
                    break;
                case '1':
                    IntArray[i] = 1;
                    break;
                case '2':
                    IntArray[i] = 2;
                    break;
                case '3':
                    IntArray[i] = 3;
                    break;
                case '4':
                    IntArray[i] = 4;
                    break;
                case '5':
                    IntArray[i] = 5;
                    break;
                case '6':
                    IntArray[i] = 6;
                    break;
                case '7':
                    IntArray[i] = 7;
                    break;
                case '8':
                    IntArray[i] = 8;
                    break;
                case '9':
                    IntArray[i] = 9;
                    break;
                default:
                    IntArray[i] = '\0';
                    break;
            }
        }


    /**
     * Null-terminate the integer array:
     */
    IntArray[StringBuff.length()] = '\0';


    /**
     * Return the array:
     */
    return IntArray;
}


/**
 * The ReverseString() function:
 *
 * A function that returns the reversed version of a provided string.
 */
std::string ReverseString(std::string NewString)
{
    char    *RevArray = new char[NewString.length()];                               // The reversed version of the provided string.


        /**
         * Perform string reversal:
         */
        for(int i = 0, d = NewString.length() - 1; d >= 0; i++, d--)
            RevArray[i] = NewString.data()[d];


    /**
     * Null-terminate the array:
     */
    RevArray[NewString.length()] = '\0';


    /**
     * Return the result:
     */
    return std::string(RevArray);
}