Questions re: 2D Array w/bubble sort

[mikhala99]

This is homework and I am using a getfile that is just a 5 row 4 column list of numbers. I can get this program to compile and when I go to run it, I get my cout text output but without my numbers and the program crashes. I am sure it is something to do with the way I call my functions. But I am so lost now. Any help is appreciated.

#include<iostream>
#include<fstream>

using namespace std;

const int ROWS = 5, COLS = 4;

//function prototypes
void Bubble_Sort(int,int,int[][COLS]);
void Show_Array(int,int,int[][COLS]);

int a[ROWS][COLS];

int main(int argc, int *argv[])
{
	int r,c,row,col;
	int a[ROWS][COLS];
    //read the data file
	ifstream inFile("data.dat");

	//fill the array
	cout<<"\nData Before Sorting:" <<endl;
	inFile >>row >>col;
 	for(r=0; r<row; r++)
 		{
 		for (c=0; c <col; r++)
			{
			cout<< a[r][c] << " ";
			}
		}

	//call the functions

 	//sort the array
 	Bubble_Sort(ROWS,COLS,a);

 	//display the sorted array
	cout<<"\nData After Exchange:" <<endl;
 	Show_Array(ROWS,COLS,a);

	return 0;
}//end of main
void Bubble_Sort(int ROWS,int COLS,int a[][4])
{      	
 	int* p = (int*)a;
 	int r,c,n(ROWS*COLS);
	for(r=0; r<(n-1); r++)
	{
            for(c=r+1; c<n; c++)
			{
 			if(p[r] > p[c])
 				{
 					int hold = p[r];
 					p[r] = p[c];
 					p[c] = hold;
 				}
 			}
	}
}//end sort
void Show_Array(int ROWS,int COLS,int a[][4])
{
 	int r,c;
 	for(r=0; r<ROWS; r++)
 	{
 		for(c=0; c<COLS; c++)
 		{
 			Show_Array(ROWS,COLS,a);
 		}
 		Show_Array(ROWS,COLS,a);
 	}
}//end show sorted
//end of file

[Freaky_Chris]

Looks to me like you only read in 2 numbers from your text file. Then you go ahead and start printing out un initialised memory space....

Chris

[mikhala99]

Looks to me like you only read in 2 numbers from your text file. Then you go ahead and start printing out un initialised memory space....

Chris

How can you tell that it is only reading in two lines? I am not arguing that that may be what is occuring, but I am not sure where the program is telling it to do that. The sort is supposed to keep going till it runs out of rows.

I have probably been staring at it too long at this point

[Freaky_Chris]

inFile >>row >>col;

This is the only line that reads data in from the file, its not looped or anything. This reads 1 integer, then skips whitespace and reads another. The fact that you don't even store them into the array at anypoint, I originally missed!

Also, you should do some error checking to make sure that the file is actually open, using

if(!inFile.good()){
  cerr<<"Unable to open file.";
  exit(0);
}

[mikhala99]

" inFile >>row >>col;" this is the only line that reads data in from the file, its not looped or anything. This reads 1 integer, then skips whitespace and reads another. The fact that you don't even store them into the array at anypoint, I originally missed!

Ok, I can understand that. It doesn't use the const int ROWS=5, COLS=4; from the top?

Also, you should do some error checking to make sure that the file is actually open, using "if(!inFile.good()){
cerr<<"Unable to open file."; exit(0);}"

ok, I should have had that. No, it wasn't reading it. However, once I got it to read it shows this crap.

Data Before Sorting:
-858993460 -858993460 -858993460 -858993460 -858993460 -858993460 -858993460 0 -
858993460 3078184 1581128 2147332096 3080192 3078252 3078192 2147332096 19799012
10 0 0 0 2147332096 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 Press any key to continue . . .

It is just frustrating that every time I fix one error, 5 more crop up. LOL

Thanks for the assist, if you can think of more... I am all ears.

Mikhala

[Freaky_Chris]

Well you are not storing them into the array such as, a[x][y]. And your show function shouldn't be recoursive like that...it doesn't even print things out, it just cause lots of problems.

Chris

[mikhala99]

Well, looks like its time to pick it apart section by section and see what runs and what doesn't. Thanks for the advice.

Mikhala