random is not so random

[fire child]

This works but the random number is always the same random number every time I compile it

is there something more random that I could use?

int length; // range of grid
int height; // range of grid
int randhigh; //random identifier 
int randlong; //random identifier
int randnum; // correlates with the number of connection nodes

cout << "How long do you want your grid? "; //set up length of grid
cin  >> length;

cout << "How tall do you want your grid? "; //set up height of grid
cin  >> height;
cout << endl;

vector<vector<double> > countgrid;

countgrid.resize(height);

for (int i = 0; i < height; ++i)
{
  countgrid[i].resize(length);
}

do{ //find a random point on the grid countgrid
  height++;
  length++;
  randhigh = rand() % height;
  randlong = rand() % length;
  height--;
  length--;
  cout << countgrid[randlong][randhigh];
  /* there is also something wronge with this code right here 
     randnum = countgrid[randlong][randhigh];*/
  cout << "<>" <<randnum<< "<>";
  randhigh++;
  randlong++;
}while (randnum <= 0);

[kempofighter]

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

Of course, the rand() function is really a pseudo-random number generator so if you want different results you have to find a way to reseed the algorithm. Perhaps you could use the system clock to seed the number generated. Each time you run the program, the time will be different.

[Tevsky]

Add the line

srand( static_cast<unsigned>( time( 0 ) ) );

At the beginning of your code

[Duthomhas]

Even so, though, you should be aware that the original premise stands:

rand() is not so random.

It is actually pretty lousy. It works well enough for simple computer games and the like... but if you want a really random number, check out http://www.random.org/

Short of that, your pseudo-random number generator should be better than the standard libc's. I recommend you google around
"c/c++ random number generator"
and
"mersenne twister random number generator"

Hope this helps.