Isomorphic trees

Two trees can be called isomorphic if they have similar structure and the only difference amongst them can be is, that their child nodes may or may not be swaped. Write a function to detect whether two trees are isomorphic

int isIsomorphic(Node root1,Node root2) {
   if(root1==null && root2==null)
       return 1;
         
   if((root1 ==  null && root2 != null) || (root1 !=null && root2 == null ))
     return 0;
             
    if(root1.val == root2.val){
             
       if(isIsomorphic(root1.left, root2.left) == 1){
            return (isIsomorphic(root1.right, root2.right));
       } else if(isIsomorphic(root1.left, root2.right) == 1){
            return (isIsomorphic(root1.right, root2.left));
       }
             
    }
         
return 0;
}