Allegro - C++ - Conway's game of life

[Ninetailsgangster]

Hi, this is my first post here. I've been programming C++ for quite a while, I'm not that good but hey we all try our best right?

Anyway at the moment I'm writing a kind of copy of Conway's game of life. For those of you not familiar with the game, it is a kind of simulation, where each box behaves acording to the boxes around it. You can Wiki it if you like, its very interesting.

Anyway I've been writing a version of this, and I can't figure out why it isn't working, can anyone help?

#include <allegro.h>

int main(){

allegro_init();
install_keyboard();
set_gfx_mode( GFX_AUTODETECT, 640, 480, 0, 0);

int Cellnum = 1;
int Cellcx = -5;
int Cellcy = 0;
int Cells [2500];
int Cellx [2500];
int Celly [2500];
int Cellsn [2500];
int Cellnc;
Cells[410] = 1;
Cells[411] = 1;
Cells[412] = 1;



while ( !key[KEY_ESC] ){




for (Cellnum; Cellnum <= 2500; Cellnum++) {

if (Cells[(Cellnum - 1)] == 1) {
Cellnc = Cellnc + 1;
}

if (Cells[(Cellnum + 1)] == 1) {
Cellnc = Cellnc + 1;
}
if (Cells[(Cellnum - 51)] == 1) {
Cellnc = Cellnc + 1;
}
if (Cells[(Cellnum - 50)] == 1) {
Cellnc = Cellnc + 1;
}
if (Cells[(Cellnum - 49)] == 1) {
Cellnc = Cellnc + 1;
}
if (Cellnc > 3) {
Cellsn[Cellnum] = 0;
}
if (Cellnc < 2) {
Cellsn[Cellnum] = 0;
}
if (Cellnc = 3) {
Cellsn[Cellnum] = 1;
}
Cellnc = 0;
}

Cellnum = 1;

for (Cellnum; Cellnum <= 2500; Cellnum++) {

Cells[Cellnum] = Cellsn[Cellnum];
Cellcx = Cellcx + 5;
if (Cellcx >= 250) {
Cellcy = Cellcy + 5;
Cellcx = 0;
}
if (Cells[Cellnum] = 1) {
rectfill( screen, Cellcx, Cellcy, (Cellcx + 5), (Cellcy + 5), makecol( 255, 0, 0));
}
if (Cells[Cellnum] = 0) {
rectfill( screen, Cellcx, Cellcy, (Cellcx + 5), (Cellcy + 5), makecol( 255, 255, 255));
}}
Cellnum = 1;
Cellcx = -5;
Cellcy = 0;



}

return 0;

}
END_OF_MAIN();

Now im more than aware that my code often makes no sense to anyone else, so ask if you don't understand something, but any help anyone could give me would be heartily appreciated.

Yours, ninetailsgangster

[DrYap]

Hi Ninetailsgangster,

As you said, I'm not sure what some of the code is doing but there are a few things that will be stopping your code from working:

Inside your first loop you do tests such as

if (Cells[(Cellnum - 51)] == 1) {
Cellnc = Cellnc + 1;
}

The first 51 times through the loop you will not be testing a value inside the array so you should always check that fist, for example

if ((Cellnum - 51) > -1 && Cells[(Cellnum - 51)] == 1) {
Cellnc = Cellnc + 1;
}

Secondly, in the second loop you do tests such as

if (Cells[Cellnum] = 1) {
rectfill( screen, Cellcx, Cellcy, (Cellcx + 5), (Cellcy + 5), makecol( 255, 0, 0));
}

Cells[Cellnum] = 1 will always return true because you are setting the value of Cells[Cellnum] to 1 which is not 0 (or true). To make this a test of equality, use the == operator, for example

if (Cells[Cellnum] == 1) {
rectfill( screen, Cellcx, Cellcy, (Cellcx + 5), (Cellcy + 5), makecol( 255, 0, 0));
}

Let me know if that helps, I'm not saying I didn't overlook anything.

[jameson91]

Hi Ninetailsgangster,

I tried your code with the Devshed c++ compiler and it worked very well. When I compiled and ran it, I got either a green or orange rectangle.
However, I made a small change to your code:

You'd written END_OF_MAIN;

I removed the semicolon ( after END_OF_MAIN and then it worked perfectly.

jameson91