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 ] ] 

**********************************************************************************************************

vector<vector<int> > Solution::generateMatrix(int num) {
   	vector<vector<int>> A(num, vector<int>(num, 0));
    int top = 0 , bottom = A.size()-1, left = 0 , right = A[0].size()-1 , dir =0 ;
    int n = 1;
    while(top<=bottom && left<=right){
        if(dir == 0){
            for(int i=left ; i<=right ; i++){
                A[top][i] = n;
                n++;
            }
                top++;
                dir = 1;
        }
        else if(dir == 1){
            for(int i=top ; i<=bottom ; i++){
                A[i][right] = n;
                n++;
            }
                right--;
                dir = 2;
        }
        else if (dir == 2){
            for(int i=right ; i >= left ; i--){
                A[bottom][i] = n;
                n++;
            }
                bottom--;
                dir = 3;
            
        }
        else{
            for(int i=bottom; i>= top ; i--){
                A[i][left] = n;
                n++;
            }
                left++;
                dir = 0;
            
        }
    }
	return A;
}