random vector of numbers

[Blaqb0x]

hi,

Im trying to create a vector of random integers in C++. Im trying to seed the rand()
function w/ the time that the system have been up. but it just gives me a vector of same numbers. running again gives a different set of same numbers. Can anyone tell my how to seed the the rand function correctly

here's my code

#################
#include "iostream"
#include "vector"
#include "time.h"
using namespace std;


int GiveRandInt(int N); // returns a random integer from 0 to N-1


int main()
{

int NumElements = 10;
int MaxElementSize = 100;


vector<int> Selection(NumElements);

for(unsigned int i = 0; i <= Selection.size() - 1; i++)
{
Selection[i] = GiveRandInt( MaxElementSize );
cout << "element " << i << ": " << Selection[i] <<endl;
}

return 0;
}


int GiveRandInt(int N)
{

srand(time(NULL)); // Seed our random numbers w/ time


//srand(GetTickCount()); // I saw a place use this but it doesn't work here. Anyone know if I need some special header for this to work?

int RandNum = rand() % N;
return RandNum;
}
#################

[GotAnyGrapes?]

The reason you are getting the same number every time is that you are reseeding it every time you want to get a random number. You only need to seed it once.

Put this line at the beginning of main() (and remove it from GiveRandInt()):

srand(time(NULL));

BTW, the way to get the clock ticks since program start is "clock()" and that is included in <ctime> (the c++ name for <time.h&gt. If you want to use clock ticks along with the time use this line instead:

srand(time(NULL) + clock());