Spiral Order Matrix II

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

Example:

Given n = 3,

You should return the following matrix:

 [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ]

 #include <iostream>  
 using namespace std;  
 int main()  
 {  
   int n = 4;  
   int **mat = new int*[n];  
   for(int i = 0 ; i < n; i++)  
       mat[i] = new int[n];  
   int dir = 0;  
   int k = 1;  
   int top = 0, bottom = n - 1, left = 0, right = n - 1;  
   while(top <= bottom && left <= right){  
     if(dir == 0){  
       for(int i = left; i <= right; i++){  
         mat[top][i] = k++;  
       }  
       top++;  
       dir = 1;  
     }  
     else if(dir == 1){  
       for(int i = top; i <= bottom; i++){  
         mat[i][right] = k++;  
       }  
       right--;  
       dir = 2;  
     }  
     else if(dir == 2){  
       for(int i = right; i >= left; i--){  
         mat[bottom][i] = k++;  
       }  
       bottom--;  
       dir = 3;  
     }else{  
       for(int i = bottom; i >= top; i--){  
         mat[i][left] = k++;  
       }  
       left++;  
       dir = 0;  
     }  
   }  
   for(int i = 0 ; i < n; i++){  
     for(int j = 0; j < n; j++){  
       cout << mat[i][j] << " ";  
     }  
     cout << endl;  
   }  
   return 0;  
 }