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1. DISCOVER . LEARN . EMPOWER
Topic : DMA
INSTITUTE - UIE
DEPARTMENT- ACADEMIC UNIT-2
Bachelor of Engineering (Computer Science & Engineering)
Subject Name: Object Oriented Programming using C++
Code:20CST151
Unit-3

2. Object Oriented
Programming
using C++
Course Objectives
2
• To enable the students to understand various stages and constructs
of C++ programming language and relate them to engineering
programming problems.
• To improve their ability to analyze and address variety of problems in
programming domains.

3. 3
CO
Number
Title Level
CO1 Provide the environment that allows students to
understand object-oriented programming Concepts.
Understand
CO2 Demonstrate basic experimental skills for differentiating
between object-oriented and procedural programming
paradigms and the advantages of object-oriented
programs.
Remember
CO3 Demonstrate their coding skill on complex programming
concepts and use it for generating solutions for
engineering and mathematical problems.
Understand
CO4 Develop skills to understand the application of classes,
objects, constructors, destructors, inheritance, operator
overloading and polymorphism, pointers, virtual
functions, exception handling, file operations and
handling.
Understand
Course Outcomes

4. Scheme of Evaluation
4
Sr.
No.
Type of Assessment
Task
Weightage of actual
conduct
Frequency of Task Final Weightage in Internal
Assessment (Prorated
Marks)
Remarks
1. Assignment* 10 marks of
each assignment
One Per Unit 10 marks As applicable to
course types depicted
above.
2. Time Bound
Surprise
Test
12 marks for each
test
One per Unit 4 marks As applicable to
course types
depicted above.
3. Quiz 4 marks of each quiz 2 per Unit 4marks As applicable to
course types
depicted above.
4. Mid-Semester Test** 20 marks for one
MST.
2 per semester 20 marks As applicable to
course types
depicted above.
5. Presentation*** Non Graded: Engagement
Task
Only for Self Study
MNGCourses.
6. Homework NA One per lecture topic
(of 2
questions)
Non-Graded: Engagement
Task
As applicable to
course types
depicted above.
7. Discussion Forum NA One per
Chapter
Non Graded: Engagement
Task
As applicable to
course types depicted
above.
8. Attendance and
Engagement Score
on BB
NA NA 2 marks

5. Why
When amount of memory to be
allocated is not known
beforehand, rather it is
determined at the time of
program run, it is called Dynamic
Memory Allocation. It leads to
efficient utilization of storage
space.
What
Dynamic memory
allocation means creating
memory at runtime. It can
be done with the help of
new operator in CPP.

6. • Introduction to DMA
• Static Memory Allocation and
Dynamic Memory Allocation
• New and delete operator
6
CONTENTS

7. Static Memory Allocation
Static memory allocation happens for Static and global variables. Memory for
these types of variables is allocated once when your program is run and persists
throughout the life of your program. When amount of memory to be allocated is
known beforehand i.e. at the time of compilation, it is known as Static Memory
Allocation. Once the memory is allocated statically, it cannot be de-allocated
during program run. So it leads to wastage of storage space. The Stack is used for
static memory allocation.
Example:
int A[100];
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8. Dynamic memory allocation
When you dynamically allocate memory, you are asking the operating
system to reserve some of that memory for your program’s use. When
your application is done with the memory, it can return the memory
back to the operating system to be given to another program. Unlike
static, the program itself is responsible for requesting and disposing
of dynamically allocated memory. In CPP this can be done with the
help of new and delete operator. The Heap is used for Dynamic
memory allocation.
8

9. Dynamic memory allocation
When amount of memory to be allocated is not known beforehand,
rather it is determined at the time of program run, it is called
Dynamic Memory Allocation. It leads to efficient utilization of
storage space. Example:
cout << " Enter number of elements: ";
cin >> N;
int *A = new int[N]; // dynamic memory allocation
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10. C++ new operator
Dynamic memory allocation means creating memory at runtime. For
example, when we declare an array, we must provide size of array in
our source code to allocate memory at compile time. But if we need
to allocate memory at runtime must use new operator followed by
data type. If we need to allocate memory for more than one element,
we must provide total number of elements required in square
bracket[ ]. It will return the address of first byte of memory
10

11. 11
ptr = new data-type;
//allocate memory for one element
ptr = new data-type [ size ];
//allocate memory for fixed number of element
Syntax of new operator

12. 12
Delete operator is used to deallocate the memory created by new operator at
run-time. Once the memory is no longer needed it should by freed so that the
memory becomes available again for other request of dynamic memory.
Syntax of delete operator
delete ptr;
//deallocate memory for one element
delete[] ptr;
//deallocate memory for array
C++ Delete operator

13. Example of c++ new and delete operator
#include<iostream.h>
#include<conio.h>
void main()
{
int size,i;
int *ptr;
cout<<"ntEnter size of Array : ";
cin>>size;
13

14. 14
ptr = new int[size];
//Creating memory at run-time and return first byte of address to ptr.
for(i=0;i<5;i++) //Input array from user.
{
cout<<"nEnter any number : ";
cin>>ptr[i];
}
for(i=0;i<5;i++) //Output arrray to console.
cout<<ptr[i]<<", ";
Example of c++ new and delete operator

15. Example of c++ new and delete operator
delete[] ptr;
//deallocating all the memory created by new operator
}
Output :
Enter size of Array : 5
Enter any number : 78
Enter any number : 45
Enter any number : 12
Enter any number : 89
Enter any number : 56
78, 45, 12, 89, 56,
15

16. Use of new and delete operator in class
#include <iostream>
using namespace std;
class Box {
public:
Box() {
cout << "Constructor called!" <<endl;
} ~Box() {
cout << "Destructor called!" <<endl;
}
}; int main() {
Box* myBoxArray = new Box[4];
16

17. Use of new and delete operator in class
delete [] myBoxArray; // Delete array
return 0;
}
Output is:
Constructor called!
Constructor called!
Constructor called!
Constructor called!
Destructor called!
Destructor called!
Destructor called!
Destructor called! 17

18. Applications of DMA
• Dynamically Allocated Memory is used to allocate memory of variable
size which is not possible with compiler allocated memory
except variable length arrays.
• Most important use of DMA is flexibility provided to programmers.
We are free to allocate and de-allocate memory whenever we need
and whenever we don’t need anymore. There are many cases where
this flexibility helps. Examples of such cases are linked list ,tree etc.
18

19. 19
Summary
In this lecture we have
discussed about DMA.
We have discussed about Static
and Dynamic memory
allocation.
Discussed about new and
delete operator.
Discussed about new and
delete operator in class.

20. Frequently Asked question
Q1 What is DMA?
When amount of memory to be allocated is not known beforehand,
rather it is determined at the time of program run, it is called Dynamic
Memory Allocation. It leads to efficient utilization of storage space.
Q2 What is static memory allocation?
When amount of memory to be allocated is known beforehand i.e. at the
the time of compilation, it is known as Static Memory Allocation. Once the
memory is allocated statically, it cannot be deallocated during program run.
So it leads to wastage of storage space.
20

21. Q3 What is new operator?
New operator is used to allocate memory at runtime .Syntax of new
operator is: ptr = new data-type;
//allocate memory for one element
ptr = new data-type [ size ];
//allocate memory for fixed number of element
Q4 What is delete operator?
Delete operator is used to deallocate the memory created by new operator at
run-time.Syntax of delete operator is
delete ptr;
//deallocate memory for one element
delete[] ptr;
//deallocate memory for array
21

22. Assessment Questions:
22
1. Which of the following is not a false statement about new operator?
a. It can’t be overloaded.
b. It returns garbage value when memory allocation fails.
c. It automatically computes the size of the data object.
d. All of these
2.Which of the following is/are valid ways to allocate memory for an
integer by dynamic memory allocation in CPP.
a. int *p = new int(100);
b. int *p; p = new int; *p = 100;
c. int *p = NULL; p = new int; *p=100;
d. Only 1,2
e. All of these

23. Discussion forum.
How can we differ Static memory Allocation and Dynamic Memory
Allocation
How to use new and delete operator ??
23
https://youtu.be/UY2_lLpDu7U
https://youtu.be/sRBB_qX4lKY

24. REFERENCES
Reference Books
[1] Programming in C++ by Reema Thareja.
[2] Programming in ANSI C++ by E. Balaguruswamy, Tata
McGraw Hill.
[3] Programming with C++ (Schaum's Outline
Series) by Byron Gottfried Jitender Chhabra, Tata McGraw
Hill.
Websites:
• https://www.geeksforgeeks.org/new-and-delete-operators-in-
cpp-for-dynamic-
• https://www.studytonight.com/cpp/memory-management-in-
cpp.php
YouTube Links:
• https://youtu.be/UY2_lLpDu7U
• https://youtu.be/sRBB_qX4lKY
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25. THANK YOU