Related to random numbers

[mmudassir6]

// this program gives random number output
#include <iostream>
#include <cstdlib> // contains function protype for rand
#include <iomanip> // for setw
using namespace std;
int main()
{
unsigned int seed;
cout << "enter seed\n";
cin >> seed;
srand (seed);
// loop 20 times
for (int counter =1; counter <= 20; ++ counter)
{
//pick random no ffrom from 1 to 6 and output it
cout << setw(10) <<(1+rand ()%100);//100 is called scaling facter & output is b/w 1 to 100
if (counter % 5==0) //if counter is divisible by 5, start a new line of output
cout << endl;
}
return 0;
}

/*my question is what is the effect on output of program of different numbers input to the int data type named seed*/

[Disch]

rand() doesn't actually give you a random number. It gives you a pseudo random number.

Computers generate pseudo random numbers with what is essentially a mathematical equation. The idea is it has a state that gets "randomized" based on running its previous state through the equation.

"seeding" the random number generator merely gives it its initial state... ie: it gives the equaltion a starting point.

So rand and srand might look something like this:

int random_state;

void srand(int seed)
{
    random_state = seed;
}

int rand()
{
    random_state = (random_state * 498721) + 7431;
    return random_state;
}

(note of course... this example is merely conceptual and is greatly simplified... rand and srand will likely operate very differently and likely will be more complex).