I have the following code
#include<iostream>
#include "time.h"
using namespace std;
void printRandomNumber()
{
srand(time(NULL));
cout << rand() % 3;
}
int main()
{
for(int i=0; i<=5; i++)
{
printRandomNumber();
}
system("pause");
}
The output is the same number repeated six times, I would like it to print out a mix of numbers.
Because you’re seeding with the same value each time – time only has second-level precision, and I’m quite sure your computer can process those six loop iterations within one second. ;-]
Seed once, at the beginning of the program.
0
Because certainly you are usually feeding the srand the same seed every time because your loop is going to take a lot less than 1 second.
The srand function should only be called once in the lifetime of your program.
You should use srand once, at the beginning. Each possible seed corresponds to a specific set of pseudorandom numbers, which are always the same when that seed is used. Since you’re going based off of seconds, you’re not giving it time to change. Therefore, you’re getting the first number of the same set of numbers each time.
This is because your random seed is essentialy the same. You have 2 solutions here :
-
You can put
srand(time(0))at the beginning of your code. This will generate better random sequence for every loop. -
If you want to have your
srand(time(0))outside of main() anyway , you can replacesrand(time(0))withsrand(rand())within your function. This will generate a random random seed , resulting in better situation.
This is what will work for your case
#include<iostream>
#include "time.h"
using namespace std;
// Reset the random number generator with the system clock.
void seed()
{
srand(time(0));
}
void printRandomNumber()
{
cout << rand() % 3;
}
int main()
{
seed();
for(int i=0; i<=5; i++)
{
printRandomNumber();
}
system("pause");
}