|Call by reference is what it actually means in english.|
suppose you have a variable X = 14 in a function called Function1.
you want to send the value of X to another fuction called Function2.
Call by value means, you make a copy of variable X and send it to Function2. whatever Function2 does to the copy it doenst change the original X in Function1. X will remain 14.
Call by reference means, you send memory address of the original X to Function2, and whatever changed Function2 makes to it, it will change the original variable X.