/*
 * ass13.c printing matrix in clockwise spiral order.
 */
#include <stdio.h>
#define ORD 20
void clockSpiral(int n, int data[][ORD]);
void printOuter(int n, int data[][ORD], int type, int ind);
int main()
{
    int n, i, j ;
    int data[ORD][ORD];
   
    printf("Enter the order of the square matrix: ");
    scanf("%d", &n);
    printf("Enter the matrix in row-major order:\n");
    for(i=0; i<n; ++i)
        for(j=0; j<n; ++j) scanf("%d", &data[i][j]);
    printf("The input matrix is:\n");
    for(i=0; i<n; ++i){
        for(j=0; j<n; ++j) printf("%d ", data[i][j]);
        putchar('\n');
    }
    printf("In clock-wise spiral order:\n");
    clockSpiral(n,data);
    return 0;
}

void clockSpiral(int n, int data[][ORD]){
     if(n == 0) {
          putchar('\n');
          return;
     }
     if(n == 1) {
        printf("%d\n", data[0][0]);
        return ;
     }
     printOuter(n, data, 1, 0);    // 3rd field is for type of row or column
     clockSpiral(n-2, (int (*)[ORD])(&data[1][1])); 
}

void printOuter(int n, int data[][ORD], int type, int ind){
     switch(type){
        case 1: 
               if(ind == n-1) printOuter(n, data, 2, 0);
               else {
                      printf("%d ", data[0][ind]);
                      printOuter(n, data, 1, ind+1);
               }
               return ;
        case 2: 
               if(ind == n-1) printOuter(n, data, 3, n-1);
               else {
                      printf("%d ", data[ind][n-1]);
                      printOuter(n, data, 2, ind+1);
               }
               return ;
        case 3: 
               if(ind == 0) printOuter(n, data, 4, n-1);
               else {
                      printf("%d ", data[n-1][ind]);
                      printOuter(n, data, 3, ind-1);
               }
               return ;
        case 4: 
               if(ind == 0) return ;
               else {
                      printf("%d ", data[ind][0]);
                      printOuter(n, data, 4, ind-1);
               }
               return ;
     }
}

/*
void clockSpiral(int n, int data[][ORD]){
     int i, j;

     if(n == 0) {
          putchar('\n');
          return;
     }
     if(n == 1) {
        printf("%d\n", data[0][0]);
        return ;
     }
     for(j=0; j<n-1; ++j) printf("%d ", data[0][j]);
     for(i=0; i<n-1; ++i) printf("%d ", data[i][n-1]);
     for(j=n-1; j>0; --j) printf("%d ", data[n-1][j]);
     for(i=n-1; i>0; --i) printf("%d ", data[i][0]);
     clockSpiral(n-2, (int (*)[ORD])(&data[1][1])); 
}
*/