So the exercise goes like this:

We are given a matrix and we are suppose to add the elements of the matrix into a vector array in a concentric way. What I mean is that we have for example a 5x5 matrix with certain values and in another vector sum[3] (I assume 3 because with a 5x5 matrix we have 3 concentric "circles" of numbers) and we add them there. I hope I was clear enough.

So anyway i remember doing something similar some weeks ago where we had to do a concentric array of numbers meaning the given the number of rows and columns the matrix should have looked like this: (I did a 3x3 here just for demonstration)

1 2 3
8 1 4
7 6 5

So basically I used the same idea here but to no avail

I don't get the values I'm supposed to get . For those who are wondering what are the values of the matrix since I read it from a file:

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

this is what I have done so far :

#include <stdio.h>
#include <stdlib.h>

#define N 5

int main()
{
    int v[N][N];
    int i, j;
    int k = 0;
    FILE*file;
    file = fopen("file", "r");
    int sum[3] = {0,0,0};

    for (i = 0; i < N; i  )
    {
        for (j = 0; j < N; j  )
        {
            fscanf(file, "%d", &v[i][j]);
        }
    }

    printf("The matrix: \n");

    for (i = 0; i < N; i  )
    {
        for (j = 0; j < N; j  )
        {
            printf("%d ", v[i][j]);
        }

        printf("\n");
    }

    while (k < 3)
    {
        for (i = 0; i < N; i  )
        {
            for (j = i; j < N - 1; j  )
                sum[k] = sum[k]   v[i][j];
    
            for (j = i - 1; j < N - 1 - i; j  )
                sum[k] = sum[k]   v[j][N - 1 - i];
    
            for (j = N - 2 - i; j >= i; j--)
            {
                sum[k] = sum[k]   v[N - 1 - i][j];
            }

            for (j = N - 2 - i; j > i; j--)
            {
                sum[k] = sum[k]   v[j][i];
            }
    
            k  ;
        }
    }

    for (i = 0; i < 3; i  )
    {
        printf("%d ", sum[i]);
    }

    return 0;
}

CodePudding user response：

I dont know if I understand your question correctly....

is this what you looking for?

int main(void) {
  int MatrixSize = 5;

  int Matrix[5][5] = {
    {1,1,1,1,1},
    {1,3,2,2,1},
    {1,2,3,2,1},
    {1,2,2,4,1},
    {1,1,1,1,1}
  };

  int Sum[3] = {0,0,0};

  int ArraySize = 3;

  for (int k = 0; k < ArraySize;   k) {
    for (int j = k; j < MatrixSize - k;   j) {
      Sum[k]  = Matrix[k][j];

      if (MatrixSize - 1 - k > k) {
        Sum[k]  = Matrix[MatrixSize - 1 - k][j];
      }
    }

    for (int i = k   1; i < MatrixSize-k-1;   i) {
      Sum[k]  = Matrix[i][k];
      Sum[k]  = Matrix[i][MatrixSize - 1 - k];
    }
  }

  for (int i = 0; i < ArraySize;   i) {
    printf("%d ", Sum[i]);
  }

  return 0;
}