Random number generator always picks the same number

Question

I'm making a small "dungeons and dragons" type of program to help demonstrate rand() command to me. It's working just fine, except it always picks 2. Never 1. Help?

#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{
    cout << "welcome to T's version of dungeons and dragons! \n Scenario:";
    int Scenario1 = rand() % 2 + 1;
    if(Scenario1==1){
        cout << "you come across a sleeping traveler, Do you ignore him, or steal his loot?";
    }
    else {
        cout << "you find an old bandit hideout in a cave. Do you ignore, or enter?";
    }

}

Or use a better generator such as one found in ``. `rand` is actively discouraged. — chris, Mar 07 '14 at 03:12
@Trevader24135, I'm not sure what you're asking. `` only exists in C++. — chris, Mar 07 '14 at 03:15
It is worth to mention that "[rand() Considered Harmful](http://channel9.msdn.com/Events/GoingNative/2013/rand-Considered-Harmful)" (Mr. STL's must watch video) — Ivan Aksamentov - Drop, Mar 07 '14 at 03:18
I changed your title to something meaningful: "programming help using C++" tells us nothing of interest - you're asking a question on StackOverflow, so we know you want programming help, and you have [c++] in your tags, so we know you are using C++. — Blorgbeard, Mar 07 '14 at 03:26

score 1 · Answer 1 · edited Mar 07 '14 at 07:52

rand() will essentially generate the same series of numbers every time if you don't seed it.

The seed determines how the rand function generates numbers. For better 'randomness', call the following once at the beginning of the program, for example as the first statement inside main:

srand(time(NULL));

This seeds the random number generator with the value of the current UNIX timestamp, which should be unique enough to guarantee a better illusion of randomness.

More information on srand here:

http://www.cplusplus.com/reference/cstdlib/srand/

Edit

As others have mentioned, it's better to use the functionality found in the <random> header, as this is a more modern approach that avoids many of the pitfalls of the srand/rand paradigm.

score 0 · Answer 2 · answered Mar 07 '14 at 03:47

rand() will always generate the number in same sequence.

To generate totally random number you can use srand(time(0)); time() is available in header file called #include <ctime>

Fore more detail please have a look :: https://www.youtube.com/watch?v=naXUIEAIt4U

Random number generator always picks the same number

2 Answers2

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