Thread: feeling proud.

i know this is jack poop to all you expert programmers out there, but I just wanted to share my last 45 minutes.. the real reason I feel good about this code i wrote is because i did the whole thing without referencing back to a tutorial, or an example (shows I'm learning something) its definitely the longest code I've written off the top of my head (even though it is SUPER short compared to an actual useful code).
also I'd like to thank the people on the forums, because I was struggling with the concept of using functions besides main, but now I've got it.. I would gladly take any tips on improving this code or tips in general! ahhh my first REAL written program. it DOES feel good

I am having trouble thinking of a way for it to loop back to main after either option is finished.. (besides exit)

Code:

#include <iostream>
#include <string>
using namespace std;


int calculator ();
int bottles_of_beer ();
int exit ();
///////////////////////CALCULATOR FUNCTIONS
double add(double x, double y)
{
    return x + y;
}
double sub(double x, double y)
{
    return x - y;
}
double multiply(double x, double y)
{
    return x * y;
}
double divide (double x, double y)
{
    return x / y;
}


////////////////////////MAIN
int main ()
{
    int choice;
    cout<<"This is a menu. please choose an option. (enter 1-3)\n";
    cout<<"1.calculator\n";
    cout<<"2.display 99 bottles of beer.\n";
    cout<<"3.exit.\n";
    cin>> choice;
    cin.ignore();
    if (choice == 1)
    {
    cout<< calculator();
    
    }
    
    else if (choice == 2)
    {
         cout<< bottles_of_beer();
    }
    
    else if (choice == 3)
    {
         int exit;
    }
               
}


////////////////////// CALCULATOR FUNCTION
int calculator ()
{
     int x=0;
     int y=0;
     int choice;
     
     cout<< "please enter 2 numbers (separated by a space)\n";
     cin>> x >> y;
     cin.ignore();
     cout<< "would you like to- \n";
     cout<< "1.add\n";
     cout<< "2.subtract\n";
     cout<< "3.multiply\n";
     cout<< "4.divide\n";
     cin>> choice;
     cin.ignore();
     
     if (choice == 1)
     {
                cout<< "answer is " << add (x, y);
     }
     
     else if (choice == 2)
     {
          cout<< "answer is " << sub (x, y);
     }
     
     else if (choice == 3)
     {
          cout<< "answer is " << multiply (x, y);
     }
     
     else if (choice == 4)
     {
          cout<< "answer is " << divide (x, y);
     }
     
     cin.get();
     
}
///////////////////////99 BOTTLES OF BEER FUNCTION
int bottles_of_beer ()
{
    int bottle_amount = 99;
    while (bottle_amount > 0)
    {
          if(bottle_amount == 2)
          {
               cout<< bottle_amount << " bottles of beer on the wall, " << bottle_amount << " bottles of beer!\n";
               cout<< "take one down, pass it around! " << --bottle_amount << " bottle of beer on the wall!\n\n";
               continue;
               }
          else if (bottle_amount == 1)
          {
           cout<< bottle_amount << " bottle of beer on the wall, " << bottle_amount << " bottle of beer!\n";
    cout<< "take one down, pass it around! " << --bottle_amount << " bottles of beer on the wall!\n\n";
    continue;
}
                            
    cout<< bottle_amount << " bottles of beer on the wall, " << bottle_amount << " bottles of beer!\n";
    cout<< "take one down, pass it around! " << --bottle_amount << " bottles of beer on the wall!\n\n";
}
cin.get();
}
///////////////////EXIT FUNCTION
int exit()
{
    return 0;
}

Very nice.

I would gladly take any tips on improving this code or tips in general!

This would be a good opportunity to replace the "if-else" chains with "switch" statements:

Code:

switch(choice)
{
    case 1:
        // execute choice 1
        break;
    case 2:
        // execute choice 2
        break;
    case 3:
        // execute choice 3
        break;
    default:
        // optional code if input is not detected above
        break;
}

O_o

When you've implemented a system where a literal has a clear association consider using tables.

"Table Driven Development" for the win.

Soma

Code:

#include <limits>
#include <iostream>

double Add
(
    double fLHS
  , double fRHS
)
{
    return(fLHS + fRHS);
}

double Empty
(
    double fLHS
  , double fRHS
)
{
    return(0.0);
}

typedef double (*OperationCallback) (double, double);

struct SOperation
{
    const OperationCallback mCallback;
    const char * mName;
};

static const SOperation kOperations[] =
{
    {Add, "Add"}
  , {Empty, "Quit"}
};

static const int kChoices = (sizeof(kOperations) / sizeof(*kOperations));

static const int kQuit = (sizeof(kOperations) / sizeof(*kOperations)) - 1;

void ShowMenu
(
    std::ostream & fOut
)
{
    for(int cChoice(0); cChoice < kChoices; ++cChoice)
    {
        fOut << cChoice << "): " << kOperations[cChoice].mName << '\n';
    }
}

int main()
{
    using namespace std;
    int sSelection(0);
    do {
        double sLHS;
        double sRHS;
        do {
            //Flush(cin);
            ShowMenu(cout);
        } while(!(cin >> sSelection) || (sSelection < 0) || (sSelection > kQuit));
        if(sSelection != kQuit)
        {
            do {
                //Flush(cin);
                cout << "Please enter operands (separated by a space): _\b";
            } while(!(cin >> sLHS >> sRHS));
            cout << kOperations[sSelection].mCallback(sLHS, sRHS) << '\n';
        }
    } while(sSelection != kQuit);
}

Thanks Matticus, Switch statements is next on my list of things to do!!

Phantomotap- I'm still pretty early on in learning (if you couldn't tell), and while i appreciate you taking the time to write all that code, not ONE bit of it made sense to me.. sorry mate, I'm just not on that level yet.

also it is a fact that main will return 0 by default, whether it is written or not.

Your line 51 does not do what you think it does. It just declares a variable called 'exit' and does not give it a value.
At it is, you don't even need to check for a case 3.
It would be a good idea to return a value from main though, say EXIT_SUCCESS.

I spotted a typo on my line 51, I wasn't aware that exit was a keyword for C++, and line 51 should actually read

Code:

int exit();

it was meant to just be a function that returned 0 so it would close the screen. would i have been able to just give the command 'exit' for option 3?

I see you're working your way through the Jumping into C++ book! ME TOO! Stick with it man! I'm only on chapter 11 lol, but so far its tons of fun! Best of luck to you, and Nice Code, I know the exact feeling you're having!

He is working his way through a book guys, hasn't reached the chapter on switches, or tables, honestly this is great for how far he is in the book...

He is working his way through a book guys, hasn't reached the chapter on switches, or tables, honestly this is great for how far he is in the book...

Who said it wasn't?

Soma

Originally Posted by rTeapot

I see you're working your way through the Jumping into C++ book! ME TOO! Stick with it man! I'm only on chapter 11 lol, but so far its tons of fun! Best of luck to you, and Nice Code, I know the exact feeling you're having!

very nice!! thanks! yea i figured "hey, alex guarantees I'll learn C++, or my money back so why the heck not!?" lol it is very fun indeed, it is however kinda frustrating when you have a great idea in mind, but still so much to learn before you could pull it off.. PATIENCE AND DETERMINATION!! glad to hear I'm not the only beginner here
cheers

Keep those great ideas written down somewhere. As you improve, and are looking for programs to practice with, you can revisit those ideas. My own greatest challenge when learning the basics of programming was thinking of what I could program for practice that was interesting while being within my capability. If you have a list of ideas on hand, this will be less of a difficulty.

good advice thanks. it will be very exciting when i can code the things I WANT to code, i feel like it will be more enjoyable coding it as well, knowing the final product i have in mind