Code

New Website - Prime 357

Steve — Sun, 06 Apr 2008 02:36:07 -0500

I've not been blogging much lately and for the last two weeks it's just been a weekly wrap-up. Most of my time has been spent 1. actually running and 2. designing my new website.

My new website (http://prime357.org) went live on Wednesday 2 April 2008. Prime357 caters for technical computer stuff, stuff that was creeping into this blog.

Since the go-live date I've been fiddling with all sorts of settings in order to re-direct all hits pertaining to Drupal and C++ to Prime357, and it works (the re-direct).

In time I'll remove the menu buttons above pertaining to Drupal & C++. That's not an overly urgent job, click on them and a re-direction occurs to Prime357 anyway.

I'll keep this blog purely for my running and other personal stuff but not geekie stuff.

Remove Vowels - # 2 - String version

Steve — Mon, 03 Mar 2008 00:03:23 -0600

I've modified the Remove Vowels program to now account for string use instead of straight out C-style string. The purpose of the program hasn't changed and that is to accept user input of a few words and strip out all the vowels. Real earth shattering stuff.

Additional to the previous version is that both upper and lowercase characters are now accounted for.

In order to reduce clutter at the end of the main() function, I reduced the exiting procedure to a function 'keep_window_open()'. On some Windows setup, it's a real pain that when running the program from the IDE the command prompt window closes automatically at the conclusion of the program. This function addresses that. If it's not needed simply comment it out.

Here's the code:

// RemoveVowels-4.cpp  --  Remove vowels from an inputted string
// Steven Taylor
// 16 Jan, 2008.
// 3 Mar, 2008 : demonstrate using type string
 
#include <iostream>
#include <string>
#include <cctype> // tolower() function
 
using namespace std;
const string VOWEL_IS = "aeiou";
        // for caps - see use of tolower() function below.
string strip(const string &str);
bool isvowel(const char c);
void keep_window_open();
 
int main()
{
    string str;
    cout << "Enter a string, any old string of words:\n";
    getline(cin, str);
    cout << "\n\nThe user input without vowels :\n" << strip(str) << endl;
    keep_window_open();  // less clutter.
    return 0;
}
string strip(const string &str)
{
    int index = 0;
    int length = str.size();
    char temp[length];
    for (int i = 0; i < length; i++)
    {
        if (!(isvowel(tolower(str[i]))))
        {
             temp[index] = str[i];
            index++;
        }
    }
    temp[index] = '\0';
    return (string)temp;        // return temp;  also works.
}
bool isvowel(const char c)
{
    for (int j=0; j < 5; j++)
    {
        if (c == VOWEL_IS[j])
            return true;
    }
    return false;
}
void keep_window_open()
{
    // only needed if the command prompt window doesn't
    // stay open.   Using a function - assists
    // with readability of the main() program
    // that is, less clutter.
    cout << "\n\n...Press ENTER to Exit System...";
    cin.clear();
    while (cin.get() != '\n')
        continue;
    cin.get();
}

I'm open to suggestions, good, bad or indifferent. Are there any other ways to achieve the purpose of this program? I'm sure there are. Whether they are more efficient or not is not the point. The point is that it gets the mind ticking considering options and alternatives. I know for one thing, I haven't explored all the std::string functions.

Consider this. If you're next assignment is along the lines of, 'check a user inputted string and remove all the characters from that string that are a part of a secondary user inputted string', that should be a piece of cake. In a few days or so, might submit such an example, based predominately upon the 'remove vowels' example.

Calculate Pace (Running Program) - # 2

Steve — Fri, 22 Feb 2008 19:29:10 -0600

I'm now into week # 14 of study, in which Classes and Objects have been introduced. (Studying from the book, C++ Primer Plus Fifth Edition, by Stephen Prata - about to commence chapter 12). In order to cement knowledge learned to date I decided to modify a program I wrote back in week 5. That program written calculates the pace of a run which is outputted as minutes per kilometre. It is only a one source code file program containing a few functions.

I've modified it, maybe modify is the wrong word, completely re-written it. This time basing the functionality upon Classes and Objects and purposely including multiple source code files (headers and definitions). Also in the process including a user decision as to the base unit (kilometres or miles).

The concept of Classes and Objects, though I understand them, opened my eyes more so towards the end of this little project. Originally, I only planned to report the pace in the units as given by user input, ie either 'mins per mile' or 'mins per km'. As I was finishing up I thought I might as well display the opposite or converted value. To my surprise, very few lines of code were required, the main bit being just another constructor passing in a reference of the user inputted details.

Without further ado, here's the code. I'll start with the main() program, hopefully you'll note that it's clean and easy to read, that's because all the work is done via the other files.

I'm open to any constructive criticism or suggestions and without further ado (again), here's the code.

/*
  Name: main.cpp
  Copyright: 
  Author: Steven Taylor
  Date: 21/02/08 21:25
  Description: Main program calling classes to work out pace of a run
*/
 
#include <iostream>
#include "run01.h"
#include "functions.h"
 
using std::cout;
using std::cin;
 
int main()
{
    char active = 'y';
    run session;
    cout << "Enter details (q to quit):\n";
    while (active == 'y' || active == 'Y')
    {
        cin >> session;
        run convert(session);
        cout << "\n" << session << " or " << convert << "\n\n";
        cout << "Another session (y or n) ";
        cin >> active;
        // anything but Y or y assumes NO
    }
     // exit routine
    cout << "\n\n...Press ENTER to Exit System...";
    clear_buffer();
    cin.get();
    return 0;
}

File # 2

/*
  Name: run01.h
  Copyright: 
  Author: Steven Taylor
  Date: 21/02/08 14:10
  Description: Header file for a run
*/
 
#ifndef RUN01_H_
#define RUN01_H_
 
class run
{
    private:
        static const int SECS_IN_MIN = 60;
        static const int MINS_IN_HOUR = 60;
        static const int SECS_IN_HOUR = 3600;
        static const double KM_PER_MILE = 1.60934;
        static const double MILES_PER_KM = 0.621371;
 
        // inputted values
        double dd;               // distance (km or miles)
        int hh;                  // hour component of time duration
        int mm;                  // minutes component of time duration
        int ss;                 // seconds component of time duration
        char unit;              // k = kilometre (default), m = miles
        // calculated values
        int mins;
        int secs;
    public:
        run();                  // default constructor
        run(double d, int h, int m, int s, char u = 'k');
        run(double d, int m, int s, char u = 'k');
        ~run();
        run(const run &r);      // converts to other unit of distance
 
        void set_run(double d, int h, int m, int s, char u = 'm');
        void set_run(double d, int m, int s, char u = 'k');
 
        void calculate_pace();
 
        void show_values();
 
 
        friend std::ostream & operator<<(std::ostream &os, const run &r);
        friend std::istream & operator>>(std::istream & is, run &r);
};
#endif

File # 3

/*
  Name: run01.cpp - definition file 
  Copyright: 
  Author: Steven Taylor
  Date: 21/02/08 14:56
  Description: 
*/
 
#include <iostream>
#include "run01.h"
#include <fstream>
#include "functions.h"
 
run::run()
{
    dd = 0.0;
    hh = mm = ss = mins = secs = 0;
    unit = 'k';
}
run::run(double d, int h, int m, int s, char u)
{
    dd = d;
    hh = h;
    mm = m;
    ss = s;
    unit = u;
    calculate_pace();
}
run::run(double d, int m, int s, char u)
{
    dd = d;
    hh = 0;
    mm = m;
    ss = s;
    unit = u;
    calculate_pace();
}
run::run(const run &r)
{
    if (r.unit == 'k')
    {
        unit = 'm';
        dd = r.dd / KM_PER_MILE;
    }
    else
    {
        unit = 'k';
        dd = r.dd / MILES_PER_KM;
    }
    hh = r.hh;
    mm = r.mm;
    ss = r.ss;
    calculate_pace();
}
run::~run()
{}
void run::set_run(double d, int h, int m, int s, char u)
{
    dd = d;
    hh = h;
    mm = m;
    ss = s;
    unit = u;
    calculate_pace();
}
void run::set_run(double d, int m, int s, char u)
{
    dd = d;
    hh = 0;
    mm = m;
    ss = s;
    unit = u;
    calculate_pace();
}
 
void run::calculate_pace()
{
    int total_secs = (hh * SECS_IN_HOUR) + (mm * SECS_IN_MIN) + ss;
    int secs_per_unit = ((double(total_secs) / dd) + 0.5);
 
    if (secs_per_unit > 0)
    {
        mins = secs_per_unit / MINS_IN_HOUR;
        secs = secs_per_unit % MINS_IN_HOUR;
    }
}
void run::show_values()
{
    std::ofstream fout;
    fout.open("debug.txt");
    fout << "hh = " << hh << " mm = " << mm << " ss = " << ss << " unit = " << unit << "\n";
    fout << "mins = " << mins << " secs = " << secs << "\n";
}
 
std::ostream & operator<<(std::ostream &os, const run &r)
{
    os << "Pace : ";
    os << r.mins << ":";
    if (r.secs < 10)
        os << "0";
    os << r.secs;
    if (r.unit == 'k')
        os << " min/km";
    else
        os << " min/mile";
    return os;
}
 
std::istream & operator>>(std::istream & is, run &r)
{
    std::cout << "Unit of distance <k>ilometres or <m>iles: ";
    if (is >> r.unit)
    {
        switch (r.unit)
        {
            case 'M':
            case 'm':
                r.unit = 'm';
                break;
            default :
                r.unit = 'k';
         }
    }
 
    std::cout << "Distance ";
    if (r.unit == 'k')
        std::cout << "(km): ";
    else
        std::cout << "(miles): ";
 
    while (!(is >> r.dd))
    {
        std::cout << "-Distance : ";
        clear_buffer();
    }
 
    std::cout << "Hours:   ";
    while (!(is >> r.hh))
    {
        std::cout << "\n-Hours: ";
        clear_buffer();
    }
 
    std::cout << "Minutes: (0 to 59): ";
    while (!(is >> r.mm) || r.mm >= r.MINS_IN_HOUR)
    {
        std::cout << "\n-Minutes: (0 to 59): ";
        clear_buffer();
    }
 
    std::cout << "Seconds: (0 to 59): ";
    while (!(is >> r.ss) || r.ss >= r.SECS_IN_MIN)
    {
        std::cout << "\n-Seconds: (0 to 59): ";
        clear_buffer();
    }
 
    r.calculate_pace();
 
    return is;
}

File # 4

/*
  Name: functions.h 
  Copyright: 
  Author: Steven Taylor
  Date: 22/02/08 16:21
  Description: General functions file
*/
#ifndef FUNCTIONS_H_
#define FUNCTIONS_H_
 
void clear_buffer();
#endif

File # 5

/*
  Name: functions.cpp
  Copyright: 
  Author: Steven Taylor
  Date: 22/02/08 16:24
  Description: General function(s) definitions 
*/
#include <iostream>
#include "functions.h"
using std::cin;
 
void clear_buffer()
{
    cin.clear();
    while (cin.get() != '\n')
        continue;
}

So that's it, what do you think?