magic_number.c

#include <stdio.h>
#define N 5

static int A[N][N];

void fillMagicSquare();

typedef struct TupleTwo
{
    int i;
    int j;
} TupleTwo;

int main() 
{
    fillMagicSquare();

    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            printf("%d ", A[i][j]);
        }
        puts("");
    }
    return 0;
}

void fillMagicSquare()
{
    int M = (N*((N*N)+1))/2;
    printf("Magic Number %d \n", M);
    
    int count = 0;
    TupleTwo position = { .i = N/2, .j = N-1 };
    while (count < N*N)
    {
        A[position.i][position.j] = count+1;

        // compute the next position
        position.i -= 1;
        position.j += 1;
       
        if (position.i == -1 && position.j == N)
        {
            position.i = 0;
            position.j = N-2;
        } else {
            position.i = position.i == -1 ? N-1 : position.i;
            position.j = position.j == N ? 0 : position.j;
        }
       if (A[position.i][position.j])
        {
            position.j -= 2;
            position.i += 1; 
            
        } 
        
        count++;
    }
}