(Sigma batch 2025) what happened in memory by shradha didi

Prateek Prajapati

Sigma batch 2025

Transcript

00:00Next, we will talk about what things are inside the memory.

00:04We write a function and call it a function.

00:08In memory, we will get a lot of special things.

00:12We have done public, static, void.

00:16If I have made a function, let's calculate sum.

00:20I will have a variable like int a, a other variable like int b.

00:24These are my formal parameters.

00:26In this sum, I have made a new variable.

00:30Int sum is equal to a plus b.

00:32Then, I will print it as well.

00:34Besides, I have made a public, static, void.

00:36Main name function.

00:38In my class.

00:40In which I know I am taking a string of arguments.

00:44I have called sum.

00:46What is inside my memory?

00:50Today, we have been able to imagine the time of the memory.

00:54My memory is something like that.

00:56Each variable is a little place.

00:58It is a name of the variable.

01:00It is a value store.

01:02We knew that there is a value store.

01:04We knew that there is a value store.

01:06The variables occupy their memory.

01:08But the functions also occupy the memory in Java.

01:12For writing functions, there is a little memory.

01:16They have some memory.

01:18Where do they have memory?

01:20They have called stack.

01:22Stack which students have heard the first time term.

01:24Stack means to keep things on top of one.

01:28Like plates in restaurants.

01:30We keep them on top of one.

01:32We keep books on top of the table.

01:34They keep on top of one.

01:36We call stack of books.

01:38Or stack of plates.

01:40Stack is to keep things on top of one.

01:44So, in Java, there is some parts that are organized in the stack.

01:48So, it shows something like this.

01:50First, there is some parts.

01:52Then, there is some parts.

01:54Then, there is some parts.

01:55Then, there is some parts.

01:56So, this way, they keep things on top of one.

01:58So, this part of memory,

02:00we call it call stack.

02:02We call it call stack.

02:04Call stack tracks.

02:05Call stack tracks.

02:06Which function has called.

02:07Which function has called.

02:08Which function has called.

02:09Or, which function is called in our memory.

02:10Now, we call it in our memory.

02:11Or, we occupy some memory.

02:12So, like a Java program is running.

02:14Like this program is running.

02:15So, what will happen first?

02:16First of all, the main function will occupy some memory.

02:21And, the amount of memory will occupy this stack.

02:24This is my call stack.

02:26I will call it a stack frame.

02:30Frame is a hole.

02:33So, the memory has occupied the main function.

02:37Now, what is stored in this memory?

02:39What is stored in this memory?

02:40In this memory, all the variables are stored.

02:42So, if I have made a sum.

02:46Then, what will happen?

02:48The main function stack frame will store the string type.

02:52And, as the main function has called the sum.

02:55So, the sum has called the call.

02:57So, the stack frame has occupied the sum function.

03:01So, the sum function will occupy this stack frame.

03:04And, what will be stored in this sum function?

03:07Because, the sum function of the integer variable is called sum.

03:11So, the integer variable will occupy this stack frame.

03:17If this sum calls some other function.

03:20So, what will happen?

03:21It will become another stack frame.

03:23In which it will be named a new function.

03:25And, its variables are stored here.

03:27So, a function occupies on the stack frame.

03:32And, what is stored in it?

03:34It is stored in the function related information.

03:37So, the input will be stored in it.

03:39It will be stored in it.

03:40The variables will be stored in it.

03:41The variables will be stored in it.

03:43So, this is why the function also needs memory.

03:45It also needs memory.

03:46And, it takes memory in the form of the call stack.

03:48Now, the whole concept of the call stack.

03:50We will be reading it again.

03:52It will be basic in the name of the recursion.

03:55So, if it is a little difficult to understand.

03:58Then, we will study Oops.

04:00We will discuss the functions in detail.

04:02We will discuss the class in detail.

04:04Then, we will study recursion.

04:05So, when we are reading recursion,

04:07We will discuss the call stack in detail.

04:09And, all of the things will be clear.

04:11So, why is it important to understand the memory?

04:15Because, in the name of the recursion,

04:17There is a wonderful technique in programming languages.

04:20There are many algorithms that use it.

04:23So, that is why,

04:24It is important to understand the call stack.

04:26Because, the call stack forms the basis of recursion.

04:29So, the function is called.

04:30So, the memory is reserved for that function.

04:33And, as we have a return statement of function.

04:36If we have a return statement here.

04:37So, as I will execute the return statement.

04:38And, in the name of the function,

04:39If I have a return statement here.

04:40So, after I execute this statement,

04:43I will reach this return statement.

04:45And, I will go into the main function.

04:49So, what the function of the call stack has occupied memory,

04:51will be removed.

04:52And, as the main function will be removed.

04:56So, the main function will be removed.

04:59So, when the function is called,

05:01It will occupy memory or place.

05:03And, when it is done,

05:05If the return statement is executed then it will be removed from the call stack.

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