Simple poker code

Hello again everyone I'm designing a code now that just deals a five card poker hand when the user presses D. I have to use pass by reference for this which I have pretty much no understanding of. The books isn't to clear and I haven't found too many useful tutorials online. Some guidance would be excellent. Just to forewarn I'm aware that there is lots of errors in this i get somewhere around 50 when i compile but they all seem to be similar.

Code:

---

#include "stdafx.h"
#include <iostream>
#include <ctime> // allows rand num gen to choose a "random" number from the clock
#include <string>
using namespace std;


void get_card(int&,int&);
int main()
{
        int card, suit, val;
        int ansr;
        srand((unsigned) time(0)); // "seed" the random number generator
       
        cout << "\n\nTo deal yourself a poker hand please press D." << endl;
        cin << ansr;
        switch (ansr)
        {
        case 'd':
        case 'D':
       
        int n = 5; // deal this many cards
        for (int i = 0; i < n; i++)       
        {
    card=get_card(suit,val)

        }
        default:
        cout << "\n\nThanks for playing." << endl << endl;
        }

        return 0;
}

void get_card(int& suit,int& val)
{       
  int suit = rand() % 4;
  int val = 1 + rand() % 13;
  switch (val)
  {
      case 1:
        cout << "Ace";
      break;
      case 11:
        cout << "Jack";
      break;
      case 12:
      cout << "Queen";
      break;
      case 13:
        cout << "King";
      break;
      default:
        cout << value;
    }

  switch (suit)
    {
      case 0:
        cout << " of Spades" << endl;
        break;
      case 1:
        cout << " of Hearts" << endl;
        break;
      case 2:
        cout << " of Diamonds" << endl;
        break;
      case 3:
        cout << " of Clubs" << endl;
    }
return;
}

---

A reference is simply a means by which to pass an object or variable to another function so that function can modify the original object or variable in the calling function.
Example:

Code:

---

void foo(int& n)
{
        n = 5;
}

int main()
{
        int n = 0;
        cout << n << endl; // 0 is output
        foo(n);
        cout << n << endl; // 5 is output
        return 0;
}

---

It wouldn't hurt for you to learn some about indenting either.
http://cpwiki.sf.net/Indentation
And don't mix tabs and spaces - indentation will look messed up outside your editor.

Looks like you are passing by reference ok, but you are assigning card=get_card(suit,val) when get_card returns void.

By the looks of things you are passing by reference for no purpose at all because you are not using the changed values after you call get_card.

In the get_card function you should not be redeclaring suit and val seeing as they are the values you are passing in, just set the values.

After your for loop within the case 'D' you should have a break;

Hope this clears up some of your errors.

BTW, in real poker hands you obviously cannot be dealt the same card twice. I don't know if you care about that now (there's more important things to work on), but if you did want to make a program plays poker then you'd want to use a different strategy for dealing cards. The typical strategy is to create a container of cards, then shuffle the container and deal by going through the container one at a time.

i thought you set it to void though BECAUSE it doesn't return a value?

Quote:

---

Originally Posted by got1sleeve

i thought you set it to void though BECAUSE it doesn't return a value?

---

Yes, if you don't return a value, you use "void" to indicate that the function is not returning a value.

But in your case, you are then assigning a variable from the result of a "no return value" function - you shouldn't do that.

--
Mats

Ok so i made some major modifciations here IMO. I changed it from void to int. As well as I have to use strings to display the card. Also i came up with the process to prevent drawing another duplicate card. Any suggestions are greatly appreciated. I'm still at about 25 errors mostly about the pass by reference not working and not being able to use a + in the string code?

Code:

---

#include "stdafx.h"
#include <iostream>
#include <ctime> // allows rand num gen to choose a "random" number from the clock
#include <string>
using namespace std;

void get_val(int&);
void get_suit(int&);
int main()
{
        int card1, card2, card3, card4, card5, suit, val;
        int ansr;
        string suit;
        string of;
        string val;
        srand((unsigned) time(0)); // "seed" the random number generator
       
        cout << "\n\nTo deal yourself a poker hand please press D. " ;
        cin >> ansr;
        switch (ansr)
        {
        case 'd':
        case 'D':
                {
                        string val=get_val(val);
                        sting suit= get_suit(suit);
                        string of= " of ";
                                card1 = val+of+suit;
                        do
                        {
                                string val=get_val(val);
                                sting suit= get_suit(suit);
                                string of= " of ";
                                card2=val+of+suit;
                        }
                        while (card2 == card1);
                        do
                        {
                                string val=get_val(val);
                                sting suit= get_suit(suit);
                                string of= " of ";
                                card3=val+of+suit;
                        }
                        while (card1==card3 || card2==card3);
                        do
                        {
                                string val=get_val(val);
                                sting suit= get_suit(suit);
                                string of= " of ";
                                card4==val+of+suit;
                        }
                        while (card1==card4 || card2==card4 || card3==card4);
                        do
                        {
                                string val=get_val(val);
                                sting suit= get_suit(suit);
                                string of= " of ";
                                card5=val+of+suit;
                        }
                        while (card1==card5 || card2==card5 || card3==card5 || card4==card5);
                }

       
   
        }
        default:
                cout << "\n\nThanks for playing." << endl << endl;
        }

        return;
}


int get_val(int&)
{       
        int val = 1 + rand() % 13;
        switch (val)
        {
                case 1:
                        cout << "Ace";
                break;
                case 11:
                        cout << "Jack";
        break;
                case 12:
                        cout << "Queen";
        break;
                case 13:
                        cout << "King";
        break;
                default:
                        cout << value;
    }
        return;
}


int get_suit(int&)
{
        int suit = rand() % 4;
        switch (suit)
    {
      case 0:
        cout << " of Spades" << endl;
        break;
      case 1:
        cout << " of Hearts" << endl;
        break;
      case 2:
        cout << " of Diamonds" << endl;
        break;
      case 3:
        cout << " of Clubs" << endl;
    }
return;
}

---

I have no idea why my tabs are all screwed in the second function i copied and pasted from VS....i got yelled at earlier for spacing out to make it look cleaner so i'll just leave it as is.....tab doesn't tab....i hate comptuers sometimes haha....i envy you all

No, no. It's because you use both tabs and spaces. If you use either just spaces or tabs, you'll be fine! Spaces are perfectly acceptable.
You get compile errors too? If you do, then you should probably post them, as well.

OK, so compile errors:

Code:

---

string suit;

---

While this isn't wrong, you already previously defined the variable as int:

Code:

---

int card1, card2, card3, card4, card5, suit, val;

---

You can't have two variables with the same name.

Code:

---

string val;

---

Same thing here - already defined.

Code:

---

sting suit= get_suit(suit);

---

How do you propose to pass a std::string to a function expecting an int?
If the function is supposed to take a string, then you need to change the function.

Code:

---

sting suit= get_suit(suit);

---

No such thing as "sting". A little typo, since it should be "string".

Code:

---

card1 = val+of+suit;

---

std::string doesn't seem to like the + operator it seems. That plus you can't store the result in an int!

Code:

---

string val=get_val(val);

---

get_val expects an int.

Code:

---

sting suit= get_suit(suit);

---

Syntax error.

Code:

---

card2=val+of+suit;

---

Same error as previous of same line.

Plus you've just duplicated code over and over. Very bad. Extract that code into a function of its own.
Now you have something to ponder about.

Ok fixed everything...code compiles and builds. Only problem is it does not display the cards. It just asks user to press D to deal and then says thanks for playing.

Code:

---

#include "stdafx.h"
#include <iostream>
#include <ctime> // allows rand num gen to choose a "random" number from the clock
#include <string>
using namespace std;


void poker(string, string, string, string, string);
void get_card(string);
int main()
{
        string card1, card2, card3, card4, card5;
        srand((unsigned) time(0)); // "seed" the random number generator
        int n=5;
        int ansr;

        cout << "\n\nTo deal yourself a poker hand please press D. " ;
        cin >> ansr;
        switch (ansr)
        {
        case 'd':
        case 'D':
                poker(card1, card2, card3, card4, card5);
                cout << card1 << endl << card2 << endl << card3 << endl << card4 << endl << card5 << endl << endl;
                       
        default:
                cout << "\n\nThanks for playing." << endl << endl;
        }

        return 0;
}


void poker(string card1, string card2, string card3, string card4, string card5)
{
        get_card(card1);
        do
        get_card(card2);
        while (card2 == card1);
        do
        get_card(card3);
        while ((card1==card3) || (card2==card3));
        do
        get_card(card4);
        while ((card1==card4) || (card2==card4) || (card3==card4));
        do
        get_card(card5);
        while ((card1==card5) || (card2==card5) || (card3==card5) || (card4==card5));

        return;
}


void get_card(string cards)
{
    int value = 1 + rand() % 13;
    int suit = rand() % 4;
        string val;
        string type;
        string of = " of ";
    switch (value)
    {
      case 1:
        val="Ace";
        break;
      case 11:
        val="Jack";
        break;
      case 12:
        val="Queen";
        break;
      case 13:
        val="King";
        break;
      default:
        val=value;
    }

    switch (suit)
    {
      case 0:
        type="Spades";
        break;
      case 1:
        type="Hearts";
        break;
      case 2:
        type="Diamonds";
        break;
      case 3:
        type="Clubs";
    }
        cards=val+of+type;

        return;
}

---

Code:

---

void poker(string card1, string card2, string card3, string card4, string card5)
{
        get_card(card1);
        do
        get_card(card2);
        while (card2 == card1);
        do
        get_card(card3);
        while ((card1==card3) || (card2==card3));
        do
        get_card(card4);
        while ((card1==card4) || (card2==card4) || (card3==card4));
        do
        get_card(card5);
        while ((card1==card5) || (card2==card5) || (card3==card5) || (card4==card5));

        return;
}

---

This is poorly indented.
Maybe this will explain it? http://cpwiki.sourceforge.net/User:E...ne_indentation

As for your problem is that you're passing by-value. You should know the difference between passing by value and by reference. Do you know this?

Quote:

---

Originally Posted by Elysia

[code]
As for your problem is that you're passing by-value. You should know the difference between passing by value and by reference. Do you know this?

---

I was told that passing strings pass by reference and not value.

and if i change the header to

Code:

---

void poker (string &card1, string &card2, string &card3, string &card4, string &card5)

---

I get the following fail.

Code:

---

Error        1        error LNK2019: unresolved external symbol "void __cdecl poker(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?poker@@YAXV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@0000@Z) referenced in function _main        Poker Lab.obj

---

Something is passed by reference only if you use & after the type. Otherwise it's by value. If it's a * after the type, it's a pointer. That's important to remember.
Your problem is that your function declaration and definition doesn't match. Always keep them the same:

Code:

---

void poker(string& card1, string& card2, string& card3, string& card4, string& card5); // Declaration
void poker(string& card1, string& card2, string& card3, string& card4, string& card5) // Definition
{
        // ...
}

---

On a side note, don't remove names for variables in the declarations either.

Quote:

---

Something is passed by value only if you use & after the type. Otherwise it's by value.

---

That is a typographical error. It should be:
Something is passed by reference only if you use & after the type. Otherwise it's by value.

Oops. Haha. Fixed. Thanks for the catch.

Quote:

---

Originally Posted by Elysia

Something is passed by reference only if you use & after the type. Otherwise it's by value. If it's a * after the type, it's a pointer. That's important to remember.
Your problem is that your function declaration and definition doesn't match. Always keep them the same:

Code:

---

void poker(string& card1, string& card2, string& card3, string& card4, string& card5); // Declaration
void poker(string& card1, string& card2, string& card3, string& card4, string& card5) // Definition
{
        // ...
}

---

On a side note, don't remove names for variables in the declarations either.

---

My teacher must have confused me then. I originally had the & in there and he said strings are pass by reference so i didn't need them in there and thats why they were causing the link error. I changed it to what you said above but i still have no output of the cards themselves. Could it be something in the switch statement? My default is "thanks for playing" and it always says that when it shouldn't right? Heres what i have so you can see the changes made.

Code:

---

#include "stdafx.h"
#include <iostream>
#include <ctime> // allows rand num gen to choose a "random" number from the clock
#include <string>
using namespace std;

void poker(string& card1, string& card2, string& card3, string& card4, string& card5);
void get_card(string& cards);
int main()
{
        string card1, card2, card3, card4, card5;
        srand((unsigned) time(0)); // "seed" the random number generator
        int n=5;
        int ansr;

        cout << "\n\nTo deal yourself a poker hand please press D. " ;
        cin >> ansr;
        switch (ansr)
        {       
                case 'd':
                case 'D':
                        poker(card1, card2, card3, card4, card5);
                        cout << card1 << endl << card2 << endl << card3 << endl << card4 << endl << card5 << endl << endl;

                default:
                        cout << "\n\nThanks for playing." << endl << endl;
        }

        return 0;
}


void poker(string& card1, string& card2, string& card3, string& card4, string& card5)
{
        get_card(card1);
        do
                get_card(card2);
        while (card2 == card1);
        do
                get_card(card3);
        while ((card1==card3) || (card2==card3));
        do
                get_card(card4);
        while ((card1==card4) || (card2==card4) || (card3==card4));
        do
                get_card(card5);
        while ((card1==card5) || (card2==card5) || (card3==card5) || (card4==card5));

        return;
}


void get_card(string& cards)
{
    int value = 1 + rand() % 13;
    int suit = rand() % 4;
        string val;
        string type;
        string of = " of ";
    switch (value)
    {
      case 1:
        val="Ace";
        break;
      case 11:
        val="Jack";
        break;
      case 12:
        val="Queen";
        break;
      case 13:
        val="King";
        break;
      default:
        val=value;
    }

    switch (suit)
    {
      case 0:
        type="Spades";
        break;
      case 1:
        type="Hearts";
        break;
      case 2:
        type="Diamonds";
        break;
      case 3:
        type="Clubs";
    }
        cards=val+of+type;
        return;
}

---

Quote:

---

Originally Posted by got1sleeve

My teacher must have confused me then. I originally had the & in there and he said strings are pass by reference so i didn't need them in there and thats why they were causing the link error.

---

There's a difference here between C-style strings and C++ std::strings. A C-style string is an array of characters, so it gets passed to a function as a pointer (which, in C, is as close as we get to pass-by-reference). A C++ string is a single type (not an array), so it needs to be passed by reference (using &) if we want changes to be seen in the main program.

well I struggle with c++ let alone know anything about c haha i stick to this forum....but any suggestions as to why the code doesn't output anything?

Let's fire up the debugger! :)
EDIT:

Duh! Of course!

Code:

---

        int ansr;

        cout << "\n\nTo deal yourself a poker hand please press D. " ;
        cin >> ansr;

---

You're reading a string or a char into an int. Ansr must be a char.
You can also remove n from the function because you aren't using it.

Also, in get card:

Code:

---

      default:
        val=value;

---

Apparently, you get an implicit conversion from int to char here, so you might as well do an explicit conversion by doing a cast and silencing a warning.