How do I create a square matrix in the C programming language? - c

Question

I wanted to know if I could get some help creating a square matrix. I know how to create the matrix, but I need to populate the matrix. I am having trouble following the logic to create the following matrix:
0 1 2 3 4 5
1 2 3 4 5 6
2 3 4 5 6 7
3 4 5 6 7 8
4 5 6 7 8 9
5 6 7 8 9 10
Here is what I have in my code thus far:
EDIT*
I have changed the else statement from arr[i][j] += 1 to arr[i][j-1] + 1
void computeMatrix(int rows, int cols, int sqMatrix[][cols]){
int i,j;
for(i = 0; i < rows; i++){
for(j = 0; j < cols; j++){
if(i == 0 && j == 0){
arr[i][j] = 0;
}
else{
arr[i][j] = arr[i][j-1] + 1; //previously arr[i][j] += 1
}
}
}
}
The issue I am having is that this code makes the following matrix:
0 1 2 3 4 5
6 7 8 9 10 11
12 13 14 15 16 17
18 19 20 21 22 23
24 25 26 27 28 29
30 31 32 33 34 35
I am not sure what type of logic to implement to get the matrix correct. I have a general idea, but I am not sure how to implement it to the code. I know that as we go down the rows, we increase by 1, and as we go through the columns, we increase by 1 as well.
Any help I could get will be greatly appreciated!

Answer 1

The elements of the first matrix can be set with:
a[i][j] = i + j;
There's no need for an if statement inside the loop. The whole thing looks like:
void computeMatrix(int rows, int cols, int sqMatrix[][cols])
{
int i,j;
for (i = 0; i < rows; i++) {
for (j = 0; j < cols; j++) {
arr[i][j] = i + j;
}
}
}

Answer 2

void computeMatrix(const size_t rows, const size_t cols, int *arr)
{
for(size_t r = 0; r < rows; r++)
{
for(size_t c = 0; c < cols; c++)
{
arr[r * cols + c] = c + r;
}
}
}
void printmatriz(const int rows, const int cols, int *arr)
{
for(size_t r = 0; r < rows; r++)
{
for(size_t c = 0; c < cols; c++)
{
printf("%2d ", arr[r * cols + c]);
}
printf("\n");
}
}
#define X 6
#define Y 6
int main(void)
{
int arr[X][Y];
computeMatrix(X,Y,&arr[0][0]);
printmatriz(X,Y, &arr[0][0]);
}

Answer 3

How do I create a square matrix in the C programming language?
You think of it as an abstract data type, using C dynamic memory allocation.
This answer gives details and code and uses flexible array members.
Read the Modern C book