public void insertKey(int data,BTreeNode r1,BTreeNode r2){
            int i = n-1;
            while(i >=0 && data < keys[i]){
                keys[i+1] = keys[i];
                i--;
            }
            keys[i+1] = data;
            int j = n;
            while(j > i+1){
                child[j+1] = child[j];
                j--;
            }
            child[j] = r1;
            child[j+1] = r2;
            n++;
        }
http://www.geeksforgeeks.org/b-tree-set-1-insert-2/
http://www.geeksforgeeks.org/b-tree-set-1-introduction-2/
src/com/interview/tree/BTree.java