Plotting Coordinates from a .txt File - c++

Question

I am finishing the second half of a two-part assignment on Conway's Game of Life. I created a function to generate a random array of 1s and 0s; the 1s represent a living cell and the zero an empty space. I created a separate function to inspect the neighborhood and make a count to determine how the game progresses. The rules: if a cell has 2 or 3 neighbors it survives, more than 3 or less than 2 it dies, and if an empty space has 3 neighbors it is "born". I even got help from you guys to wrap the screen using the modulus, but I am having trouble importing a .txt file to finish part two. Here is the code for part one:
#include <iostream> //includes input-output stream
#include <time.h> //includes time function
#include <iomanip> //includes setprecision function
#include <unistd.h> //includes sleep function
#include <fstream> //includes ifstream function
using namespace std; //using standard library
int master[24][79]; //initializes primary data array
int h = 24; // initializes height variable
int w = 79; // initialises width variable
int noOfCycles; //initialize cycles variable
void gen0 (int master[24][79]); // creates initial generation
void life(int master[24][79]); //initializes life function
void copy(int arrayX[24][79], int arrayY[24][79]); //initializes cycle update function
void print(int master[24][79]); //initializes print function
void fillPercent (int master[24][79]); //initializes percentage calculating function
int main() //initialize main function
{
cout << "How many cycles would you like to run?"; //prompt user to input cycles
cin >> noOfCycles; //user inputs cycles
srand (time(0)); //creates initial randomness
gen0(master); //creates initial generation
for (int k = 0; k <= noOfCycles; k++) //prints gen0 and cycles 50 times
{
print(master); //prints current array
fillPercent(master); //calculates/prints fill percentage
cout << " Cycle #" << k << " Author: Mikhail Morgan" << endl << endl;
//prints cycle number and signature
life(master); //calls life function
sleep(1); //delays output by 1 second
} //end width loop
} //end main function
void gen0 (int master[24][79])
{
for(int j = 0; j < h; j++) //height loop
{
for (int i = 0; i < w; i++) //width loop
master[j][i] = rand() % 2; //creates random generation 0
} //end height loop
}
void print(int master[24][79]) //Prints array
{
for(int j = 0; j < h; j++) //height loop
{
for(int i = 0; i < w; i++) //width loop
{
if(master[j][i] == 1)
cout << '0'; //print living cells as zeros
else
cout << ' '; //print dead cells as spaces
} // end width loop
cout << endl;
} // end height loop
} //end print function
void fillPercent (int master[24][79]) // calculates fill percentage
{
double fillNumber = 0; //resets every cycle
for (int i = 0; i < h; i++ ) //width loop
{
for (int j = 0; j < w; j++ ) //height loop
{
fillNumber += master[i][j]; //increments fill number
} //end height loop
} //end width loop
cout << endl << fixed << setprecision(2) << (fillNumber/(w*h))*100; //print percentage
} //end fillPercent function
void life (int master[24][79]) //generates/kills cells based on neighborhood
{
int temp[24][79]; //temporary array for manipulating data
copy (master, temp); //copy array onto temp
for(int j = 0; j < h; j++) //height loop
{
for (int i = 0; i < w; i++) //width loop
{
int count = 0; //intialize neighbor count variable
count = master[(j-1+h) % h][i % w] + //searches down
master[(j-1+h) % h][(i-1+w) % w] + //down left
master[j % h][(i-1+w) % w] + //left
master[(j+1+h) % h][(i-1+w) % w] + //up left
master[(j+1+h) % h][i % w] + //up
master[(j+1+h) % h][(i+1+w) % w] + //up right
master[j % h][(i+1+w) % w] + //right
master[(j-1+h) % h][(i+1+w) % w]; //down right
//cell dies if count falls below 2 or rises above 3
if(count < 2 || count > 3)
temp[j][i] = 0;
//cell stays alive if it has two neighbors
if(count == 2)
temp[j][i] = master[j][i];
//cell either stays alive or gets born if three neighbors
if(count == 3)
temp[j][i] = 1;
} //end width loop
}//end height loop
copy(temp, master); //copy temp back to main array
} //end life function
void copy(int arrayX[24][79], int arrayY[24][79]) //Copy machine
{
for(int j = 0; j < h; j++) //height loop
{
for(int i = 0; i < w; i++) //width loop
arrayY[j][i] = arrayX[j][i]; //temporary arrays used for copying
} //end height loop
} //end copy function
I know, using namespace std is lame af but it's mandated by my dinosaur-of-a-professor.
My problem is that for part two he wants us to stream the coordinates for the initial generation from a file that he supplied called GliderGun.txt. I am using Xcode and Im 99% sure that I have the file in the right location: I can see it in the right hand menu inside the same folder as main.cpp, and I can see the original copy in the Finder menu next to main.cpp. The first line is not a coordinate pair, it is the total number of coordinates in the file... Im not sure what the purpose of that is, and I suspect its whats messing me up. Here is the text from the file itself:
36
1 25
2 23
2 25
3 13
3 14
3 21
3 22
3 35
3 36
4 12
4 16
4 21
4 22
4 35
4 36
5 1
5 2
5 11
5 17
5 21
5 22
6 1
6 2
6 11
6 15
6 17
6 18
6 23
6 25
7 11
7 17
7 25
8 12
8 16
9 13
9 14
Here is the code for the function that replaces gen0. All I did was replace the call for gen0 with getPattern and altered the definition to look like this:
void getPattern (int master[24][79]) //generates Glider Gun
{
ifstream infile("GliderGun.txt", ios::in);
infile.open("GliderGun.txt", ios::in);//opens .txt file
int numOfCoordinates; // number of coordinate pairs
int i, j; // x, y coordinates
infile >> numOfCoordinates;
for (int a = 0; a < numOfCoordinates; a++)
{
infile >> i >> j;
master[j][i] = 1;
}
infile.close(); // closes .txt file
}
The console produces a blank 24x79 array. I sense that I have a looping problem but I dont know enough about how ifstream works to fix it. The coordinates are listed as (x y) or as defined by my other loops, (j i). I don't need the console to print the file I just need it to write 1s in the coordinates that are listed. Thanks for any advice!

Answer 1

Just from trying to reason about your code, there are two problems that arise from a drop-in replacement of getPattern where gen0 used to be:
You don't initialize any of the slots of your array to zero.
You're reading in the number of lines as an x-coordinate for one of the cells, all of the x-coordinates as y-coordinates, most of the y-coordinates as x-coordinates, and not reading the last y-coordinate.
There are two simple enough changes you can make to fix this.
Before reading from the file set the value in all cells of your 2D-array to 0.
Even if you're not doing anything with it, read in the number of lines from the file before looping over the coordinates.
Unrelated to your code, the text file does not need to be in the same directory as the source file, it needs to be in the same directory that the program is executed from. I don't know where the execution will be done from in XCode, but it might be worth testing directly from your computer's shell, if you know how.
Edit:
The part of getPattern where you read from the file could look something like this:
int num_coordinates; // This will be the number of coordinate pairs your file says it has.
int i, j; // These will be your x, y coordinates.
infile >> num_coordinates;
for (int loop_ct = 0; loop_ct < num_coordinates; loop_ct++) {
infile >> i >> j;
master[j][i] = 1;
}