2D Array & random numbers

[Keeper]

I've got a two dimensional array which needs the first and third rows to match. In a "for" loop, I'm creating a random number (0-9)and assigning it to the first element in the array, and then incrementing the column element and repeating the process, giving me four random numbers in row1 (element[0]). Here's what I'm working with:

int i;
int Game[3][4] = {0};

for (i=0; i<=3; i++)
{
	Game[0][i] = rand() % 10;
	Game[2][i] = Game[0][i];
}

Is there a way to set one row equal to another without looping through the two as I have here? Also, each time I run this piece of code I get the same "random" numbers. I tried using randomize() and random() but couldn't make it work. I kept getting erros that randomize and random were not declared variables. How can I ensure the numbers I'm getting differ each time?

[Dave McLelland]

You need to seed the random number generator to get a random sequence.

Use: srand( (unsigned)time( NULL ) );

This starts the generator based on the computers clock.

To copy a row in an array yo do need to copy each element individually.

[Dave McLelland]

Just noticed that you initialise the array with { 0 }.

You probably know this, but that only sets Game[0][0] = 0

The remainder of the array will have values that are undetermined, in a debug build, these might be 0, but a release build they could be anything.

[Keeper]

I haven't tried using srand() before. Here's and exmaple I pulled out of a book, which I tried to adapt to my code. I get teh same undeclared variable errors though.

#include <time.h>
#include <stdlib.h>
#include <iostream.h>

int main()
{
	int i;

	randomize();

	for (i=1; i<5; i++)
	{
		cout << "\n" << random(10);
	}

	return 0;
}

[Paul McKenzie]

Originally posted by Dave McLelland
Just noticed that you initialise the array with { 0 }.

You probably know this, but that only sets Game[0][0] = 0

Not true. If there are fewer entries in the initialization list than entries in the array, the remaining elements are set to 0.

Regards,

Paul McKenzie

[Dave McLelland]

You are right of course. It says so in the ARM.

[STL MAN]

Use a vector

[Keeper]

Use a vector

Sorry, I don't know what that is or how to use it.