Generating different random number in second call

Question

I am trying to implement the craps game in C++, rules are given below. So I created a function which will generate two numbers for me, sometime this function needs to be called twice, but when it is called for the second time its giving me the same random number it gave me the first time.

I want to randomize the numbers I get in the the second call to rollDice() function. How do I do that?

Example output 1:
Player rolled 3 + 4 = 7
Player won!

Example output 2:
Player rolled 2 + 2 = 4
Point is 4
Player rolled 2 + 2 = 4 Player won!

Example output 3:
Player rolled 1 + 5 = 6
Point is 6
Player rolled 1 + 5 = 6
Player won!

Game rules: Rule: A player throws two 6 face dice, if their sum is 7 or 11, they Win. if the sum is 2,3 or 12 they loose. if it's 4,5,6,8,9,10,12 it becomes a "point" and the player has to roll again. The player then keeps rolling until he hit the "point" again and he wins and loose if he hits a 7.

Code:

#include<iostream>
#include<ctime>
#include <cstdlib>

using namespace std;

//Generating two rand numbers from 1 to 6
int rollDice()
{
    srand(time(0));
    int face1 = 1 + rand()%6;
    int face2 = 1 + rand()%6;
    int sum = face1 + face2;

    cout << "Player rolled " << face1 << " + " << face2 << " = " << sum << endl;
    return sum;
}

string gameStatus; //Hold status of game; WIN, CONTINUE, LOST
int sumOfDice = rollDice();
int point = 0; //This will hold sum of dice if it's default case defined below in Switch.

int main()
{
     switch(sumOfDice)
     {
         case 7:
        case 11:
            gameStatus = "WIN";
            break;

        case 2:
        case 3:
        case 12:
            gameStatus = "LOST";
            break;

        default:
            gameStatus = "CONTINUE";
            point = sumOfDice;
            cout << "Point is " << point << endl;
     }

     while (gameStatus == "CONTINUE")
     {
         int rollAgain = rollDice();
         if (rollAgain == point)
            gameStatus = "WIN";
         else if (rollAgain == 7)
            gameStatus = "LOST";
     }
     if (gameStatus == "WIN")
        cout << "Player won!";
     if (gameStatus == "LOST")
        cout << "Player lost!";
}

You're supposed to call `srand()` once not every time. You're re-seeding the random sequence with the same seed, so you're getting the same first number of said sequence. Call srand at the beginning of main. Or if you can use c++11 make use of `` (I need a template for this comment, I use this advice almost every week...) — Borgleader, Dec 04 '14 at 13:50
@Borgleader You could a detailed and self-answered question, then flag all others as duplicates. — Colonel Thirty Two, Dec 04 '14 at 13:54

score 3 · Accepted Answer · answered Dec 04 '14 at 13:51

srand(time(0));

This resets the seed for the random number generator to the current time. Do this only once, when the program starts. If you do it twice within the same second (so that time returns the same value), then you'll get the same sequence of random numbers each time.

Generating different random number in second call

1 Answers1