Matrix Class - Wrong Outputs?!

Question

https://code.sololearn.com/cq24J951TxgI/#

I have the following Matrix Class.

Now I tried to create a function to Split the Matrix into Sub-Matrices of size m_r * m_c each and save them in a Matrix of Matrix - Matrix** for easy access...

friend Matrix** Split(Matrix m,int m_r,int m_c)
{
if((m.r%m_r==0)&&(m.c%m_c==0)&&(m_r<m.r)&&(m_c<m.c))
{
int new_r=m.r/m_r;
int new_c=m.c/m_c;
Matrix** matrix=new Matrix*[new_r];
for(int i=0;i<new_r;i++)
{
matrix[i]=new Matrix[new_c];
for(int j=0;j<new_c;j++)
matrix[i][j].Reset(m_r,m_c);
}
for(int i=0;i<m.r-m_r;i++)
{
for(int j=0;j<m.c-m_c;j++)
{
for(int k=0;k<m_r;k++)
{
for(int l=0;l<m_c;l++)
{
matrix[i][j].mat[k][l]=m.mat[i+k][j+l];
}
}
}
}
return matrix;
}
else
{
//Do Something else.
}
}

Now, the problem is that the outputs are wrong. Eg -

When Input -
1 1 0 0
1 1 0 0
0 0 1 1
0 0 1 1

Output -
1 1
1 1 // Correct

1 0 0 0
1 0 //Wrong 0 0

1 1 0 0
0 0 //Wrong 0 0

1 0 1 1
0 1 //Wrong 1 1

Why is the output wrong?

P.S. - I tried Increasing the limits of i and j's loop by 1, but that stops the program.

Answer 1

SUCCESS!!!!

int row = 0;
int column = 0;

for (int i = 0; i<m.r; i += m_r){
for (int j = 0; j < m.c; j += new_c) {
for (int x = i; x < i + new_r; x++){
row++;
for (int y = j; y < j + new_c; y++){
column++;
matrix[i/2][j/2].mat[row - 1][column - 1] = m.mat[x][y];
}
column = 0;
}
row = 0;
}
}

output:
First set
2 2
1 1
Second set
1 1
1 1
Third set
1 1
1 1
Forth set
1 1
2 2

Answer 2

#code of the day
code crashes my phone

2000+ lines of code

Answer 3

woooooo! I am so happy that I was able to play a small part in your success! now what is the plans for this code? is it part of some larger project? anymore mods planned?

Answer 4

Nice! Well keep us in the loop as to your progress. It is a very neat header file so far

Answer 5

So correct output should be?

1 1
1 1

0 0
0 0

0 0
0 0

1 1
1 1

Edit: I will have a look on my pc after dinner. the code crashes the app on my phone. Not sure if I can help. But I will look

Answer 6

@jay
Yes, That's what the output should be.
Thank You for your initiative to help...

Answer 7

@Kinshuk: Could you update the code to include the code you have. I have put in the above friend function, but dont know how to use it to get output lol. Rather than spend forever trying to get to the same point you are at. It would help me heaps. Then I can concentrate on the problem at hand.

:) told you I might not be much help :)

Answer 8

https://code.sololearn.com/cccB9W06ocb6/?ref=app

Here is the code after the update...

Answer 9

Oh Srry
Lemme update that...

Answer 10

Mine loops twice for some reason now... so confuse

Answer 11

I removed the i loop and it behaves
for (int j = 0; j < m.c; j += new_c) {
for (int x = j; x < j + new_r; x++) {
for (int y = j; y < j + new_c; y++) {
cout << x << " " << y << endl;
}
}
}

Output:

0 0
0 1
1 0
1 1
2 2
2 3
3 2
3 3

Answer 12

imma dumb ass lol -- the i is rows, so it the x.... hahahha its :1:20am here.. sooo

for (int i = 0; i<m.r; i += m_r){
for (int j = 0; j < m.c; j += new_c) {
for (int x = i; x < i + new_r; x++)
{
for (int y = j; y < j + new_c; y++)
{
cout << x << " " << y << " = " << m.mat[x][y] << endl; }
}
}
}
OUtput
0 0 = 2
0 1 = 2
1 0 = 1
1 1 = 1
0 2 = 1
0 3 = 1
1 2 = 1
1 3 = 1
2 0 = 1
2 1 = 1
3 0 = 1
3 1 = 1
2 2 = 1
2 3 = 1
3 2 = 2
3 3 = 2

Answer 13

So how does the new matrix work (the one we are passing the data too?

Answer 14

@jay
Congo! You did it!
Thanks!

Answer 15

i wouldnt have slept! I had to have one last go before I went to bed! You are truly welcome! I loved the challenge! Keep up the awesome questions!

Answer 16

nope yours code

Answer 17

It is pretty awesome. Having played with it myself I can testify to its greatness

Answer 18

@Kinshuk. I had a thought this morning. Could we replace the 2 in the assignment formula with new_r and new_c respectively?

Answer 19

so it would be:
matrix[i/new_r][j/new_c]

Edit: Not tested. just a thought

Answer 20

Just finished dinner. Going to look now..
Fish and Chips if you are curious