random number generator

After searching the net for an hour to find a good random number generator, this is the best I found. From what I understand it works off of time as seconds and minutes change, but I would like to dive in further to understand the purpose of these 5 items...

srand
rand
time
NULL
<ctime>

Code:

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

int main()

{
srand(time(NULL));
cout << rand();

}

Originally Posted by Brian_Jones

After searching the net for an hour to find a good random number generator, this is the best I found.

Poor thing After you have read through the article that I linked to below, and have experimented with this a little more, take a look at what is offered by Boost.Random.

Originally Posted by Brian_Jones

From what I understand it works off of time as seconds and minutes change

That refers to the way that the PRNG is seeded, not the way that the PRNG actually works. The standard library's pseudorandom number generator's algorithm depends on the implementation.

Originally Posted by Brian_Jones

but I would like to dive in further to understand the purpose of these 5 items...

srand
rand
time
NULL
<ctime>

srand is used to seed the PRNG, rand is used to get a random number in the range [0, RAND_MAX], std::time(NULL) is used to get the current time, NULL is a macro for zero, and <ctime> is the standard header for std::time. I suggest that you read Prelude's article on Using rand().

Thank you!