Recomposing the Conway's Game code in C

Hi here I have conway's game code in c, how can i mod it so that it reads and obtains initial state from an external txt file instead and then print out the corresponding new state? I really want to know how to do that thanks!

Code:

---

#include <stdio.h>
#include <stdlib.h>

#define ROWS 20
#define COLS 20

#define GETCOL(c) (c%COLS)
#define GETROW(c) (c/COLS)

#define D_LEFT(c)  ((GETCOL(c) == 0) ? (COLS-1) :  -1)
#define D_RIGHT(c)  ((GETCOL(c) == COLS-1) ? (-COLS+1) :  1)
#define D_TOP(c)    ((GETROW(c) == 0) ? ((ROWS-1) * COLS) : -COLS)
#define D_BOTTOM(c) ((GETROW(c) == ROWS-1) ? (-(ROWS-1) * COLS) : COLS)


typedef struct _cell
{
    struct _cell *neighbour[8];
    char curr_state;
    char next_state;
}cell;


typedef struct
{
    int rows;
    int cols;
    cell* cells;
} world;


void evolve_cell(cell *c)
{
    int count=0, i;
    for (i=0; i<8; i++)
    {
        if (c->neighbour[i]->curr_state) count++;
    }
    if (count == 3 || (c->curr_state && count == 2)) c->next_state = 1;
    else c->next_state = 0;

}
 
 
void update_world(world *w)
{
    int nrcells = w->rows*w->cols, i;
    for (i=0; i<nrcells; i++)
    {
        evolve_cell(w->cells+i);
    }
    for (i=0; i<nrcells; i++)
    {
        w->cells[i].curr_state = w->cells[i].next_state;
        if (!(i%COLS)) printf("\n");
        printf("%c",w->cells[i].curr_state ? '#' : ' ');
    }
}


world* init_world()
{ 
    world* result = (world*) malloc(sizeof(world));
    result->rows = ROWS;
    result->cols = COLS;
    result->cells = (cell*) malloc(sizeof(cell) * COLS * ROWS);
   
    int nrcells = result->rows * result->cols, i;
   
    for (i = 0; i < nrcells; i++)
    {
        cell* c = result->cells + i;
           
        c->neighbour[0] = c+D_LEFT(i);
        c->neighbour[1] = c+D_RIGHT(i);
        c->neighbour[2] = c+D_TOP(i);
        c->neighbour[3] = c+D_BOTTOM(i);
        c->neighbour[4] = c+D_LEFT(i)  + D_TOP(i);
        c->neighbour[5] = c+D_LEFT(i)  + D_BOTTOM(i);
        c->neighbour[6] = c+D_RIGHT(i)  + D_TOP(i);
        c->neighbour[7] = c+D_RIGHT(i)  + D_BOTTOM(i);
       
        c->curr_state = rand() % 2;
    }
    return result;
}


int main()
{
    srand(3);
    world* w = init_world();
   
    while (1)
    {
        system("CLS");
        update_world(w);
        getchar();
    }
}

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Well for starters, you can write the part where it actually tries to open and read a file.


Quzah.

yes, and I figure it might be something like this:

Code:

---

int c;
char inName[200];
FILE *In, *Out;

    //get file name from user
    printf("Please enter a text file name: ");
    scanf("%s", inName);
        In = fopen(inName, "r");
        //test if file exists
        if(In == NULL)
        {
            printf("ERROR: cannot open file");
          return 1;
            abort();
        }

---

But it seems quite impossible how it can read from the file cell by cell and test it should be alive or dead...!

Quote:

---

Originally Posted by Noya

yes, and I figure it might be something like this:

Code:

---

int c;
char inName[200];
FILE *In, *Out;

    //get file name from user
    printf("Please enter a text file name: ");
    scanf("%s", inName);
        In = fopen(inName, "r");
        //test if file exists
        if(In == NULL)
        {
            printf("ERROR: cannot open file");
          return 1;
            abort();
        }

---

But it seems quite impossible how it can read from the file cell by cell and test it should be alive or dead...!

---

Why do you think it is impossible?

> here I have conway's game code in c
Lemme guess, you found it, or you were given it.

I would suggest you put that code to one side for the moment, while you get some practice in reading files.

> yes, and I figure it might be something like this:
So you managed to use fopen(), carry on reading the book/manual page to learn about fgetc / fgets / fread and do some testing to see which is going to be best for you in terms of reading the file.

Quote:

---

Originally Posted by tabstop

Why do you think it is impossible?

---

Well, it actually is impossible... until he can get it to save the information first.

Can't read an empty file...

Of course figuring out how to save the data will also tell him how to read it...

After long hours of testing I believe I have finally pulled something together...but still one of the major trouble I frequently run into during the trials are reading the characters from the target external txt file, I used '#' to represent alive cells, and '-' (for come reason my compiler has poor recognition of space character ' '). But even with '-', there still seem to be strange error momentarily, meaning it reads without error only when the dimension is within 25 by 25, which I can't figure out why.
why?
why!

Code:

---

void Read_in (void)
    {
        //local variables
        FILE *input_file;
        char file_name[100];
        int x, y;
        char temp;

                //get filename from user
                printf("Enter name of file: ");
                scanf("%s", file_name);

        //        strcat(Fname,".txt");

                //open file
                input_file = fopen(file_name, "r");
                if (input_file == NULL)
                {
                    printf("Could not open input file\n");
                        exit(1);
                }

                //read data into array
                for (y=0 ; y<YMAX; y++)
                {
                    for (x=0; x<XMAX; x++)
                        {
                            temp = getc(input_file);
                                if (temp == EOF)
                                {
                                    printf("Unexpected end-of-file in %s", file_name);
                                    //printf("End character is %c at [%i][%i]", temp, y, x);
                                   
                                        return;
                                }
                                if (temp == '#')
                                    board [y][x] = 1;
                                else if (temp == '-')
                                    board [y][x] = 0;
                                else
                                {
                                    //printf("Unknown character found in file: [%i] [%i]", y, x);
                                    printf("Unknown character found, that character is %c at [%i][%i]", temp, y, x);
                                        return;
                                }
                        }
                        getc(input_file); //throw away newline character
                }
                fclose(input_file);
        }

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This might be a bit obvious but why don't you just write 1 and 0 to the disk file?

There's not anything here that would die at the magic number of 25. Most command prompt windows come, out of the box, at 24 lines tall, so if you have a larger size you'll have to scroll to see it.