Thread: Advice on Accelerated C++ problem 4.2

I'm starting to practice using C++, and have read some info on using C++11 and am trying to use it a little bit.

I tried to follow the intent of the problem and did not use pow from <cmath>.

I plan on learning how to use template, and will turn the double number into a template to tackle other data types for problem 4.3.

I was hoping to make sure i'm using uniform intialization correctly, using the right data type for setw and if my template idea would work.

Code:

// IntDoubling.cpp : Defines the entry point for the console application.//


#include "stdafx.h"
#include <iostream>
#include <iomanip>


using std::cout;
using std::setw;


int DoubleNumber(int numToDouble);
int GetNumWidth(int numToCount, int base = 10);


int DoubleNumber(int numToDouble) 
{
    return numToDouble * numToDouble;
}


int GetNumWidth(int numToCount, int base)
{
    int number_of_digits{ 0 };


    do {
        ++number_of_digits;
        numToCount /= base;
    } while (numToCount);


    return number_of_digits;
}


int main()
{
    int maxNum{ 100 };


    // get width of max num
    int maxNumW{ GetNumWidth(maxNum) };


    // get width of max num ^ 2
    int maxNumDubW{ GetNumWidth(DoubleNumber(maxNum)) };


    for (int i = 0; i <= maxNum; ++i)
    {
        cout << "Num: " << setw(maxNumW) << i << " doubled is " << 
            setw(maxNumDubW) << DoubleNumber(i) << std::endl;
    }


    return 0;
}

I added in using a template for SquareNumber. Coming from using mainly c for years, I'm finding this to be so cool.

Code:

// IntDoubling.cpp : Defines the entry point for the console application.//


#include "stdafx.h"
#include <iostream>
#include <iomanip>


using std::cout;
using std::setw;


template <typename T>
T const& SquareNumber(T const& a);
int GetNumWidth(int numToCount, int base = 10);


template <typename T>
T const& SquareNumber(T const& a)
{
    return a * a;
}


int GetNumWidth(int numToCount, int base)
{
    int number_of_digits{ 0 };


    do {
        ++number_of_digits;
        numToCount /= base;
    } while (numToCount);


    return number_of_digits;
}


int main()
{
    int maxNum{ 100 };


    // get width of max num
    int maxNumW{ GetNumWidth(maxNum) };


    // get width of max num ^ 2
    int maxNumDubW{ GetNumWidth(SquareNumber(maxNum)) };


    for(int i = 0; i <= maxNum; ++i)
    {
        cout << "Int Num: " << setw(maxNumW) << i << " doubled is " << 
            setw(maxNumDubW) << SquareNumber(i) << std::endl;
    }


    for (int i = 0; i <= maxNum; ++i)
    {
        double y{ i * 1.0 };
        cout << "Double Num: " << setw(maxNumW) << y << " doubled is " <<
            setw(maxNumDubW) << SquareNumber(y) << std::endl;
    }    


    return 0;
}