Why is it wrong to write RETURN ? ( postorder traversal )

Question

void Postorder( IntPtr head ) {
    if ( head != NULL ) {
        return Postorder( head -> left ); // problem
        return Postorder( head -> right ); // problem
        printf( "%d\n", head -> data );
    } // if
}

Why is it wrong to write RETURN? I want to know.

I think it will find head-> left all the way to the bottom, if head -> left is NULL, it will go back to the above one layer and start looking for head -> right, and finally output

Answer 1

return means "I'm finished here, so don't execute any more code in this function. So when the code encounters the first return statement it returns from the function, and doesn't execute the second call to PostOrder or the printf statement.

Off the top of my head, I suspect that simply removing the word return from both of those statements will fix the problem:

void Postorder( IntPtr head ) {
    if ( head != NULL ) {
        Postorder( head -> left );
        Postorder( head -> right );
        printf( "%d\n", head -> data );
    } // if
}

Answer 2

You return before you printf .