1. Jun 29, 2006

### Miss_lolitta

Hi,,
I am hoping that you will help me. I have trouble how can do this homework:
Write a program that allows the user to input a number of integers such as N, and then stores them in an integer matrix where:

1- The dimension of matrix = NXN.
2-Entries of matrix can take any number from 0-2.
3- Arrangement of entries of first row is the same arrangement of entries of first column.
4-The diagonal of matrix =o.
5- Total of every row =4,Also Total of every column.

Then, the program displays the result.

Your help would greatly be appreciated

Respectfully,,
Miss_Lolitta

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2. Jun 30, 2006

### Luminous Blob

Is there a particular language that the program is to be written in?

3. Jun 30, 2006

### Anttech

hey perhaps we can sit your exams for you too?

At least try and do it, and post what progress you have gotten through!

4. Jun 30, 2006

### buddyholly9999

Isn't this in the wrong section? Shouldn't it be in the homework section?

5. Jun 30, 2006

### Miss_lolitta

I would like to write this program in C++.I learn the programming language at an institute,and I am not expert in this branch but I try to become better with your first help.

I would be so ever grateful if you could help me on how to go about writing this program.

thanks,,

6. Jun 30, 2006

### DaveC426913

OK, forget about the programming language, forget about the computer. Pick up a pencil.

Design you logic first. Start at a high level, then break it down.
1] Gets integer from user: N.
2] Creates a matrix: NxN.
3] Fills in the diagonal values with zeros.
4] ?? - You must decide on your algorthim for checking against your rules.

Clearly step 4 is the bulk of the program. How do you propose to check?
Brute force?
000 000 000 = No.
000 000 001 = No
000 000 002 = No
000 000 010 = No
etc.
Is there a better way to do this? Knowing the rules you have to stay within, and the possible values (0-2), are there any steps you can eliminate? (Note that of the above tests, only 2 of them are valid, considering the "diagonal rule". You don't even need to test them.)

Hint: you're going to be needing a lot of loops and a lot of 'if's.

There is no point in going anywhere near a programming language or a computer until you've worked out your logic.

Last edited: Jun 30, 2006
7. Jul 1, 2006

### Miss_lolitta

Really, forget about the programming language, forget about the computer. Look at this method to solve this problem in maths:

1] Gets integer from user: N. such as N=3

2] Creates a matrix: 3x3

X Y Z
X Y Z
X Y Z

3] Fills in the diagonal values with zeros.

0 Y Z
X 0 Z
X Y 0

>>> then we have the following system:

0 Y Z = 4
X 0 Z = 4
X Y 0 = 4

>>> by solving this system we have a unique solution:X=2,Y=2,Z=2

>>> So, we have matrix

0 2 2
2 0 2
2 2 0

Hint: we have a symmetry between diagonals of matrix

I know that there is relation between maths and CS to solve mathematical problems..because of this I would like to study the programming languages.