the program generates a random number when its suposed to be a random letter

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  1. #1
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    Question the program generates a random number when its suposed to be a random letter

    The program compiles and executes fine but it generates a random number between 1-20 when i want it to generate a letter between c,d,h,and s.
    thanx


    Code:
    #include <iostream>
    #include <stdlib.h>
    #include <ctime>
    #include <cstdlib>
    #include <string>
    using namespace std;
    int main()
    {
          char randsuit;
          const char suit[] = "cdhs";
          srand(time(NULL));
          randsuit = suit[rand() % (sizeof(suit)-1)];
          cout << randsuit << endl;
          system("PAUSE");
          return 0;
    }

  2. #2
    Registered User caroundw5h's Avatar
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    You might need some more help on this hopefully someone else will help you out as well.


    As far as i understand it the sizeoff keyword will return the number of bytes in a given expression. so your code
    Code:
    randsuit = suit[rand() % (sizeof(suit)-1)];
    is reading the size of the expression in that line. Not the actually elements of the array.


    What you might want to do is assign the letters c,d,h, s or whatever as individual elements of the suit array, ex: char suit = {"c", "d", "h", "s", "EXIT"} Not sure the actually code in C++, I'm still learning C so...

    Then your random function would be random() % 4 i think, whatever elements suits is, and you can designate what it should do when it returns a number in the length of suit ex: 1- 4.

    As it stands it seems that your the number of bytes in the expression with sizeof. Hope that helps a bit. I'm sure someone else can explain it better.
    Last edited by caroundw5h; 12-25-2003 at 12:04 AM.

  3. #3
    and the hat of int overfl Salem's Avatar
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    Code looks good - works pretty well too.

    The sizeof() is not the problem in this instance. On a char array, (sizeof(suit)-1) == strlen(suit)
    But it is evaluated at compile time not at run-time
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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