Time stamp 6:40

#1

confusion between * and &
why T& and *f;

#2

also expain what does f holds

#3 
	T& operator [](string key){
		T* f=search(key);
		if(f==NULL){
			insert(key,0);
			f=search(key);
		}
		return *f;
	}

f is a pointer of type T which holds the address of node containing key
now we have to return address of node so we return value inside pointer which is *f;

as we are returning address or reference of node so return type will be T&

if you have more doubts regarding this feel free to ask
i hope this helps
if yes hit a like :heart:: and don’t forgot to mark doubt as resolved :grinning:

#4

what does *f hold here

#5

as told it is pointer
which contains the address of that node whose data==key

which we get form search function

#6

T* search(string key){
int idx=hashFn(key);
node*temp=table[idx];
while(temp!=NULL){
if(temp->key==key){
//returns address where value is stored
return &temp->value;
}
temp=temp->next;
}
return NULL;
}
this is the search function so f is address of value
so *f should be value?
so how t& and *f have same data type

#7

and the how does price["key]=10 gives correct result

#8

in the operator[] overloading function
we store this address in the pointer f
so inside operator[] overloading function
f is pointer
*f is address

#9

f should be a pointer but *f should be a value?
as in search function we return &temp->value

#10

yes it is a value
but the pointer contains address
so the value of f is address

i hope now it is clear

#11

noooooooooooooooooooooooooooooooo
when i do cout<<f;
what will i get
and when i do cout<<*f;

#12

cout<<f
give error as it is pointer
cout<<*f
this will print address of node

#13

sorry but i am unable to understand

#14

exactly which thing you don’t understand

#15

#include
using namespace std;
int main() {
int y=10;
int*x;
x=&y;
cout<<x;
}
here x is giving an address
but u are saying it will be error

#16

Screenshot from 2020-08-03 18-26-02
Screenshot from 2020-08-03 18-26-021366×768 134 KB

something like this is happening please explain

#17

https://www.learncpp.com/cpp-tutorial/74a-returning-values-by-value-reference-and-address/#:~:text=Return%20by%20reference,-Similar%20to%20return&text=When%20a%20variable%20is%20returned,when%20returning%20structs%20and%20classes.

#18

okay right

now i am briefing the whole discussion

f is pointer
*f is value of pointer which is key

now we are returning *f by reference as return type is T& so that we can update value in main also

1 Like
#19

now got it thanksssssss