Random number issue.

[Tick Talos]

Ok. So its a simple program. What I want it to do is each time I run it have the "friendlyCave" be a randomly chosen number between 1 and 2. Then the "game" comes when the user has to choose between one or two to see if he guessed correctly and got the friendlyCave. However when I run the program choosing 1 always gets you to be eaten and choice 2 always is the choice of the dragon sharing his treasure. Please help.
-T

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


int main()
{
    cout << "You are in a a land full of dragons. In front of you, you see ";
    cout << "two caves. \nIn one cave, the dragon is friendly and will share his";
    cout << " treausure with you. \nThe other dragon is greedy and hungry, and ";
    cout << " will eat you on sight." << endl;
    
     int cave; 
     cout << "\nWhich cave do you choose 1 or 2?\n"; 
     cin >> cave; 
     
    int friendlyCave = rand() % 2 + 1;
     
     if (cave == friendlyCave)
     {
          cout << "The dragon pops his head out and shares his treasure.";
     }
     else
          cout << "The dragon pops his head out and eats you in one bite!";
     
     int exit; 
     cin >> exit; 
      
     return 0; 
       
 }  

[Tresky]

It sounds to me that friendlyCave is not being evaluated correctly.
You need to initialize a random seed.

srand (time(NULL));
// You'll need to include the time.h library 

Add this line in the beginning of your code to set the seed based on the time of the system.

This should fix the problem for you.

[Tick Talos]

Worked beautifully. Cheers man. So did that just seed a number starting at null? I recognize "srand" but when I used it before it was srand(time(0)) under the library <ctime>.

[Tresky]

Well, NULL is a C++ macro that is defined as 0. So essentially... they are the same.

Also, the ctime library is completely equivalent to the time.h library as far as I know. I believe there could possibly be a little difference because time.h was used in C and ctime was made to transfer to C++ I believe.

I've never varified that, but that's what I think. Haha. HOWEVER, I do know that time.h and ctime are completely equivalent as far as we are concerned here. Haha.

srand(time(0)) under the library <ctime>

EQUALS

srand (time(NULL));
// You'll need to include the time.h library

So did that just seed a number starting at null?

Forgot to answer this... Yes. :D

[Disch]

TECHNICALITY ALERT!!!!!!

Well, NULL is a C++ macro that is defined as 0. So essentially... they are the same.

It's not a standard macro. I think it's actually a WinAPI macro. And I also think it might be slightly different depending on who's defining it. Sometimes it's 0, sometimes it's (void*)0, etc.

Though in C++11, they actually did introduce a standard keyword for this... nullptr. So I recommend using that instead of NULL.

because time.h was used in C and ctime was made to transfer to C++ I believe.

Mostly right. The <ctime> header also puts things in the std namespace, and may have overloaded versions of some of the functions (which are legal in C++... but in C function overloading is not allowed). In C++ it's generally better to use the <cxxx> headers instead of the <xxx.h> headers.

[Tresky]

Thanks! :D

I'm glad you corrected me. :)