Matrix from numbers

[CodeCmade1]

Hi, I need help for this matrix.I'm trying to do but I can't think of solution how to do the middle part.Have to look like this...

(0 0 0 0 0 0 0 0 0 0)
(0 1 0 0 0 0 0 0 0 0)
(0 0 2 0 0 0 0 0 0 0)
(0 0 0 3 0 0 0 0 0 0)
(0 0 0 0 4 0 0 0 0 0)
(0 0 0 0 0 5 0 0 0 0)
(0 0 0 0 0 0 6 0 0 0)
(0 0 0 0 0 0 0 7 0 0)
(0 0 0 0 0 0 0 0 8 0)
(0 0 0 0 0 0 0 0 0 9)

I do not know how to fill the other side and I think there is a better way to solve this problem, or the entire matrix.If you can please paste code.
Get this far for now:

  #include <iostream>

using namespace std;

int main()
{
    int matrix[10][10];
    int a = 0;

    for(int x=0;x<10;x++)
    {
        for(int y=0;y<10;y++)
        {
            matrix[x][y];
        }
    }

    for(int x=0;x<10;x++)
    {

        for(int y=0;y<x;y++)
        {

            cout<<matrix[x][y] << " ";

        }
        cout << a;

    cout<<endl;  
    a++;
    }
    return 0;
}

[keskiverto]

1. Avoid global variables. There is no reason for the "matrix" to be outside of the main().

2. You have to assign a value to each element on line 15. Use a conditional to test whether an element is on the diagonal or not.

Hint: ternary operator ? :

Hint: With http://stackoverflow.com/questions/629017/how-does-array100-0-set-the-entire-array-to-0 you don't need nested loops for setting the diagonal values.

[CodeCmade1]

1.Done.
2.What is the condition for checking the diagonal elements.
Could you write me some code with comments of steps that you do...i'll be so grateful!

[giblit]

The basic algorithm would be like this:

For each row
    output (
    for each column
        if column == row output row
        else output 0
    output )

EDIT:

What is the condition for checking the diagonal elements

With a square that would mean that the column and row are the same.

Could you write me some code with comments of steps that you do...i'll be so grateful!

I tried to give you pseudo code without giving you code. Since giving pseudo code was pretty much the answer anyways. Though as keskiverto mentioned you can use ? : (ternary operator) instead of if/else


The alternative solution would be:

assign all values to 0 --you can use default initialization with int arrays by assign {} or {0}.
for each row (column and row will be same in a square)
    assign array[row][column] the row

[CodeCmade1]

I know there's a much easier way to build this program, it would be better someone to show the easier way.
I did it this way and it's working:

#include <iostream>

using namespace std;

int main()
{
    int matrix[10][10];
    int a = 0;
    int q = 9;

    
    for(int x=0;x<10;x++)
    {
        for(int y=0;y<10;y++)
        {
            matrix[x][y] = {};
        }
    }
    

    for(int x=0;x<10;x++)
    {

        cout << "( ";

        for(int y=0;y<x;y++)
        {


            cout<<matrix[x][y] << " ";
        }


    cout << a << " ";
    for(int z=0;z<q;z++)
        {
            if(matrix[x]!=matrix[q])
            {
                matrix[x][z]={0};
                cout << matrix[x][z] << " ";
            }
        }
        cout << ")";
    cout << endl;
    a++;
    q--;
    }

    return 0;
}

[CodeCmade1]

I decided to write more simple solution:

#include <iostream>

using namespace std;

int main()
{
    int matrix[10][10];

    for(int row=0;row<10;row++)
    {
        cout << "( ";

        for(int col=0;col<10;col++)
        {
            if(row==col)
            {
                cout << row << " ";
            }
            else cout << "0 ";
        }
        cout << ")" << endl;
    }
    return 0;
}

I think it's good and much simple than the last one.
Thank you so much: giblit and keskiverto!!!!
You really helped me to understand this...thanks again.

[giblit]

The second one is very similar to the first algorithm I mentioned. The second one would look like

#include <iostream>

int main()
{
    std::size_t const size = 10u; //size = rows and columns (since it is a square)

    int matrix[size][size] = {}; //initialize all to 0

    for(int row = 0; row < size; ++row) //row and column will be same since diagonal
    {
        matrix[row][row] = row;
    }


    //output if you want

    return 0;
}

Edit with your code earlier,

            if(row==col)
            {
                cout << row << " ";
            }
            else cout << "0 ";

could be std::cout << (row == col ? row : 0) << ' ';