Thread: Game of life program

Hi,
Again a question from the book(Problem solving and program design in C)
I solved the question.But output not as I want to be.I mean it doesn't work as game of life
Code:

Code:

#include <stdio.h> 
#include <stdlib.h>
#define ROWS 25
#define COLS 25
void game_of_life(char arr[][COLS+2]);
int checkx(char arr[][COLS+2], int row, int col);
int main(void)
{
	char array[ROWS+2][COLS+2],n_array[ROWS+2][COLS+2];
	int i, j, r_integer[ROWS+2][COLS+2], num_gen;
	for(i=0;i<ROWS+2;i++){
		for(j=0;j<COLS+2;j++){
			r_integer[j][i] = (rand()%2);
		}
	}
	for(i=0;i<ROWS+2;i++){
		for(j=0;j<COLS+2;j++){
			  if(r_integer[j][i] == 0)
                  array[j][i]=' ';
              else
				  array[j][i]='X';            
			}
		}			
	for(i=0;i<ROWS+2;i++){
		for(j=0;j<COLS+2;j++){
			printf("%c", array[j][i]);
		}
	}
	for(num_gen=0;num_gen<2;num_gen++){
		printf("\nGeneration: %d\n", num_gen+1);
		game_of_life(n_array);
		for(i=0;i<ROWS+2;i++){
			for(j=0;j<COLS+2;j++){
				n_array[j][i]=array[j][i];
			}
		}
		for(i=0;i<ROWS+2;i++){
			for(j=0;j<COLS+2;j++){
				printf("%c", array[j][i]);
			}
		}
	}
	return(0);
}
void game_of_life(char arr[][COLS+2])
{
	int i, j, num_neighbors=0;
	for(i=1;i<COLS+2;i++){     
		for(j=1;j<ROWS+2;j++){
			if ((arr[j][i])=='X'){
				num_neighbors=checkx(arr, j, i);
				if (num_neighbors <= 3 || num_neighbors >= 2)
					arr[j][i]='X';
				if (num_neighbors >= 4)  
					arr[j][i]=' ';
				else
					arr[j][i]='X';
            }
			else {
				num_neighbors=checkx(arr, j, i);
                if(num_neighbors == 3)   
					arr[j][i]='X';
                else
					arr[j][i]=' ';
              }
          }
      }
}
		
int checkx(char arr[][COLS+2],int row, int col)
{
      int num_neighbors = 0;
      if ((arr[row-1][col-1])=='X')
          num_neighbors++;
      if ((arr[row-1][col])=='X')
          num_neighbors++;
      if ((arr[row-1][col-1])=='X')
		  num_neighbors++;
      if ((arr[row][col-1])=='X')
          num_neighbors++;
      if ((arr[row][col+1])=='X')
          num_neighbors++;
      if ((arr[row+1][col-1])=='X')
          num_neighbors++;
      if ((arr[row+1][col])=='X')
          num_neighbors++;
      if ((arr[row+1][col+1])=='X')
          num_neighbors++;
      return(num_neighbors);
}

Output is not changing

X XXXX XX X XX X XX XXXX XXX X XXXX X X X X X XXX X X XXX X X X X X XX X X XX XXX X X XXX X XXXXXXXXXX XX X XX X XXX X X X X XXXX X X X XXXXX XX XX X XXXXX XX X XXX XXX X X X X XX X XXX X XX X XXX X X X XX XXXX X XXXX XXX X XX X X XX X XX XXXXX XX XX X X X XX X X XXX X XXX X X XXXX XX X X X X XXX X X XX XXXXX X X XX X X XXXX X XX XXX X XX XX XXXXX XXXX XX X XX X XXXXX X XX X X X X X XXXX X X XX XX XX X XXXXX XXX XXXXX X XX X X XXXX XXXXX XXX XXXXX XXXXXX XX XX X XXX XXXX XXX XXX XX XXX X X X X X X XX XXX X X X XXXXXX XX X XX XXX
Generation: 1
X XXXX XX X XX X XX XXXX XXX X XXXX X X X X X XXX X X XXX X X X X X XX X X XX XXX X X XXX X XXXXXXXXXX XX X XX X XXX X X X X XXXX X X X XXXXX XX XX X XXXXX XX X XXX XXX X X X X XX X XXX X XX X XXX X X X XX XXXX X XXXX XXX X XX X X XX X XX XXXXX XX XX X X X XX X X XXX X XXX X X XXXX XX X X X X XXX X X XX XXXXX X X XX X X XXXX X XX XXX X XX XX XXXXX XXXX XX X XX X XXXXX X XX X X X X X XXXX X X XX XX XX X XXXXX XXX XXXXX X XX X X XXXX XXXXX XXX XXXXX XXXXXX XX XX X XXX XXXX XXX XXX XX XXX X X X X X X XX XXX X X X XXXXXX XX X XX XXX
Generation: 2
X XXXX XX X XX X XX XXXX XXX X XXXX X X X X X XXX X X XXX X X X X X XX X X XX XXX X X XXX X XXXXXXXXXX XX X XX X XXX X X X X XXXX X X X XXXXX XX XX X XXXXX XX X XXX XXX X X X X XX X XXX X XX X XXX X X X XX XXXX X XXXX XXX X XX X X XX X XX XXXXX XX XX X X X XX X X XXX X XXX X X XXXX XX X X X X XXX X X XX XXXXX X X XX X X XXXX X XX XXX X XX XX XXXXX XXXX XX X XX X XXXXX X XX X X X X X XXXX X X XX XX XX X XXXXX XXX XXXXX X XX X X XXXX XXXXX XXX XXXXX XXXXXX XX XX X XXX XXXX XXX XXX XX XXX X X X X X X XX XXX X X X XXXXXX XX X XX XXX

Part of the problem could be your random number generator...
First you're using it without calling srand() to initialize a new sequence... thus you will always get the same sequence.
Second some random number generators when used with %2 either give you 0 and 1 alternately or have a strong bias to 1.

Try something like this...

Code:

#include <time.h>

int main (void)
  { srand(time(NULL));  // do this only once
 
// to generate 0 or 1
x = (rand() % 100) > 50 ? 1 : 0;

Originally Posted by CommonTater

Part of the problem could be your random number generator...
First you're using it without calling srand() to initialize a new sequence... thus you will always get the same sequence.
Second some random number generators when used with %2 either give you 0 and 1 alternately or have a strong bias to 1.

Try something like this...

Code:

#include <time.h>

int main (void)
  { srand(time(NULL));  // do this only once
 
// to generate 0 or 1
x = (rand() % 100) > 50 ? 1 : 0;

Nothing changed.Generations are same;
@Salem

Look at when you change each array.

In particular, you need to create a new array completely before making any changes to the old one.
That is, life/death is calculated on the old (and unmodified) array. You're changing it as go

I'm calling the game_of_life with a new array (n_array), and adding values of n_array to old array

Code:

for(num_gen=0;num_gen<2;num_gen++){
		printf("\nGeneration: %d\n", num_gen+1);
		game_of_life(n_array);
		for(i=0;i<ROWS+2;i++){
			for(j=0;j<COLS+2;j++){
				n_array[j][i]=array[j][i];
			}

Code:

if (num_neighbors <= 3 || num_neighbors >= 2)

That line looks suspicious. Is it not true for all values of num_neighbors?

This is confusing, too:

Code:

checkx(o_arr, j+1, i+1)

Why add one to i and j (which should be row and column...or is it vice versa?) before you send? Why not send the actual current location and let checkx do the math?

I think checkx needs a bounds test as well (for when it runs up against the limits of the valid grid), but could be wrong.

Did you read my post?

Originally Posted by mike65535

Did you read my post?

Yes, sorry.
And the final version of my code is:

Code:

#include <stdio.h> 
#include <stdlib.h>
#include <time.h>
#define ROWS 25
#define COLS 25
void game_of_life(char o_arr[][COLS], char n_array[][COLS]);
int checkx(char arr[][COLS],int row, int col);
int main(void)
{
	char array[ROWS][COLS],n_array[ROWS][COLS];
	srand(time(NULL));
	int i, j, r_integer[ROWS][COLS], num_gen;
	for(i=0;i<ROWS+2;i++){
		for(j=0;j<COLS+2;j++){
			r_integer[j][i] = (rand() % 100) > 50 ? 1 : 0;
		}
	}
	for(i=0;i<ROWS;i++){
		for(j=0;j<COLS;j++){
			  if(r_integer[j][i] == 0)
                  array[j][i]=' ';
              else
				  array[j][i]='X';            
			}
		}			
	for(i=0;i<ROWS;i++){
		for(j=0;j<COLS;j++){
			printf("%c", array[j][i]);
		}
	}
	for(num_gen=0;num_gen<2;num_gen++){
		printf("\nGeneration: %d\n", num_gen+1);
		game_of_life(array,n_array);
		for(i=0;i<ROWS;i++){
			for(j=0;j<COLS;j++){
				array[j][i]=n_array[j][i];
			}
		}
		for(i=0;i<ROWS;i++){
			for(j=0;j<COLS;j++){
				printf("%c", array[j][i]);
			}
		}
	}
	return(0);
}
void game_of_life(char o_arr[][COLS], char n_array[][COLS])
{
	int i, j, num_neighbors=0;
	for(i=0;i<COLS;i++){     
		for(j=0;j<ROWS;j++){
			if ((o_arr[j][i])=='X'){
				num_neighbors=checkx(o_arr, j, i);
				if (num_neighbors >= 4)  
					n_array[j][i]=' ';
				else if( num_neighbors <4 && num_neighbors >= 2)
					n_array[j][i]='X';
            }
			else {
				num_neighbors=checkx(o_arr, j, i);
                if(num_neighbors == 3)   
					n_array[j][i]='X';
                else if ( num_neighbors < 2)
					n_array[j][i]=' ';
              }
          }
      }
}
		
int checkx(char arr[][COLS],int row, int col)
{
      int num_neighbors = 0;
      if ((arr[row-1][col-1])=='X')
          num_neighbors++;
      if ((arr[row-1][col])=='X')
          num_neighbors++;
      if ((arr[row-1][col-1])=='X')
		  num_neighbors++;
      if ((arr[row][col-1])=='X')
          num_neighbors++;
      if ((arr[row][col+1])=='X')
          num_neighbors++;
      if ((arr[row+1][col-1])=='X')
          num_neighbors++;
      if ((arr[row+1][col])=='X')
          num_neighbors++;
      if ((arr[row+1][col+1])=='X')
          num_neighbors++;
      return(num_neighbors);
}

And its output is

X XXXXXX XXX X XXXXXX X X XX X XXXXX X X X XXXXXX XX XX X XXXXXX X X XX XX X XXX X X XXXXXX X XX X X XXX XXXXX XX X XXXXXXXXX XX XX XXX X X X X XX X X XX XXXX X X X X X X X XX XX X XX X XX XXX X X XX XX X X X X X X XX X X XX XX XXX XXXXX XXXXXX XXX XXXXXXX X X X XX XX X X X X X XXXX XXXX XXX X X XX XXXXXXX X XX XX XX XXX X XXXXXXXX XX X X X XX X XXXXX XXX X XX X X X XX XX XX XX XX X XX XXXXX XXX X X X XXXXX X X X X X XXX XX XXXXX X X X XX XX XX X XX XXXXXX XX X X
Generation: 1
X �X XXXXX XXXX XM X � ��XXX X XX� D� � � XX �XX�XXXF XX� X XX XXXXX X� X XX Xg �� XX Ľ X �XXB�X X X| � ��X�XXX X X0 X/X�X ���XXX X|fX f X8q�XXX XXXX XX X X ��X� XXX X' i � X�� � X X �X X XXX X X X XD� XX2J D� �3� XXX� X�X �XXXXXXXJXXX5 XX XGX �� �� XXXNX�XX� X /XXXU�XXXX XXX � X� X/XX XXXX XX�f� � X XXX X޿X XX qXXXX XXX XXXXi XX X�X 8q Xg� � XXX X XX r �XX
Generation: 2
XX X XX XXXXX X X X �XXXX X XXX� XX XXX X X �XX�XXXXF XX� XXX XXXXXX X X X XX X XXXX � X X � X �XXXXX X X X| �X�X X X X 0X X/XXX ���XXX XX|fX XX8X�XXX XXXXXXXXXX � XX X X X X X X XX� X XXXX �X XXX X XXXX X XD�X X2 �XX� XXX� XXX �XXXXX XJXX 5 XXX XGX X�� � XX XNX�XXX� X /X U�XXXX XXXX � X�X XXX XX XX XXXXXf X X X X X޿XXXX qXXX XXXXXX X X XXXX�X 8X g� XXXXX X X X XXX

C'mon, guy. So many things wrong. You should test with a known pattern that you can verify by eye before going ahead with an entire program with zillions of errors.
In main...

Code:

for(i=0;i<ROWS+2;i++){
		for(j=0;j<COLS+2;j++){

This will go beyond the edge of the array.
- You should print a "\n" for each row so that the output looks good.
- inside game_of_life() you must use loops like this:

Code:

	for(i = 1; i < COLS - 1; i++){ 
		for(j = 1; j < ROWS - 1; j++){

... because you can not use the edges due to the way checkx() works
- the logic for number of neighbors and whether there's a birth, death, or no change needs to be corrected.
- there is an error inside checkx for one of the cell checks.

Originally Posted by nonoob

C'mon, guy. So many things wrong. You should test with a known pattern that you can verify by eye before going ahead with an entire program with zillions of errors.
In main...

Code:

for(i=0;i<ROWS+2;i++){
		for(j=0;j<COLS+2;j++){

This will go beyond the edge of the array.
- You should print a "\n" for each row so that the output looks good.
- inside game_of_life() you must use loops like this:

Code:

	for(i = 1; i < COLS - 1; i++){ 
		for(j = 1; j < ROWS - 1; j++){

... because you can not use the edges due to the way checkx() works
- the logic for number of neighbors and whether there's a birth, death, or no change needs to be corrected.
- there is an error inside checkx for one of the cell checks.

Hi, I'm new at programming,anyway...
I changed the logic for number of neighbors:

Code:

for(i=1;i<COLS-1;i++){     
		for(j=1;j<ROWS-1;j++){
			if ((o_arr[j][i])=='X'){
				num_neighbors = checkx(o_arr, j, i);
				if( num_neighbors <4 && num_neighbors >= 2)
					n_array[j][i]='X';
				else
					n_array[j][i]=' ';
            }
			else {
				num_neighbors=checkx(o_arr, j, i);
				if (num_neighbors == 3)  
					n_array[j][i]='X';                
				else 
					n_array[j][i]=' ';
              }
          }
      }

Is it true now?

Yes that part of the logic is correct now.