Binary Tree Sum Replacement

#1

I have not understood how this code is error free.

  1. The function has a return type of ’ int ’
    However in the driver function , we have just called the function without assigning it to an integer variable.
  2. The function replaceSum(node *root) :
    is supposed to make change to the original tree.
    So how did this code work without passing the root by reference . Shouldn’t the code be
    int replaceSum(node *&root) ?
    How did the changes reflect?
    https://ide.codingblocks.com/#/s/22746
    line number : 160
#2

@jaiskid , can you please help me out with this?
Thanks in advance.

#3

@krishnamanohar199 hey krishna the reason is that to not passing with reference is we are not adding a new node or deleting node the existing node. we have already given tree we are changing value present inside the particular nodes of the given tree. I repeating we are not creating a new tree instead we are modifying a given tree.

1 Like
#4

Alright, so if we dont append/delete the present structure, we dont need to pass that by reference?
I thought when a modification is being done , it must be passed by reference.

What about the return type of the function?

#5

If you haven’t passed it by reference ,
it means that a copy has been created in the function and we are modifying the copy’s node data.
Then how is it being reflected in the actual program?

#6

@krishnamanohar199 yes change will reflected in the actual program.basically it is like bhaiya create a instance of the tree and modified it but if bhaiya want to change in respect of structure he has pass by reference
remember two things
1 value can be change by creating copy of the given tree
2 structure of the tree will not change with the instance you have to use deep copy instead of the shallow copy

#7

By structure I meant, the values of the data , sorry for the confusion :slight_smile: .
In the function , we have passed the root node.
Now a copy of the actual root has been created for the function. Whatever value I change in the function must pertain to the copy and must not reflect in the original root theoretically unless I pass it by reference, right?

#8

@krishnamanohar199 yes it like you can create multiple copies of the tree and try different things with given tree without harming the original one.

#9

Then how did the change reflect?
Is there an option to chat? Because this seems really confusing…

#10

@krishnamanohar199 come on chat request

#11

I’m sorry , how do I do that ?

#12

@krishnamanohar199 there is chat request option in ask doubt portal

#13

I have initiated one, is there anyone online ??

#14

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