SRM OODP Unit 1 Study Guide 📖

Object-Oriented Programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code: data in the form of fields (often known as attributes or properties), and code, in the form of procedures (often known as methods).

Key Concepts:

• Class: A blueprint or prototype from which objects are created. It defines the variables and methods common to all objects of a certain kind.
• Object: A real-world entity that has state and behavior. It is an instance of a class.

Procedure Oriented Programming (POP) focuses on functions, while Object-Oriented Programming (OOP) focuses on data.

A Use Case Diagram represents the dynamic behavior of a system. It shows the interaction between the user (Actor) and the system (Use Cases).

+--------------------------------+
|           ATM SYSTEM           |
|                                |
| Customer ---> ( Withdraw Cash) |
| Customer ---> ( Check Balance) |
| Customer ---> ( Deposit Money) |
+--------------------------------+

• Actor: External entity interacting with the system (e.g., Customer, Admin). Represented by a stick figure.
• Use Case: A specific function or action the system performs. Represented by an oval.
• System Boundary: The box indicating the scope of the system.

An Activity Diagram represents the workflow and execution process of a system. It models the logic from activity to activity, functioning similarly to a complex flowchart.

  [ Start ]
      |
      v
( Insert Card )
      |
      v
( Enter PIN ) ---> [ Invalid? ] ---> ( Reject & Eject )
      |
   [ Valid? ]
      |
      v
( Select Account )
      |
      v
  [ Finish ]

A Class Diagram maps out the static structure of a system by detailing its classes, attributes, operations, and the relationships among objects.

+------------------+
|     Student      |  <-- Class Name
+------------------+
| - name : string  |  <-- Attributes (Private)
| - id : int       |
+------------------+
| + study() : void |  <-- Methods (Public)
| + exams() : void |
+------------------+

Visibility Marks: + Public, - Private, # Protected.

A standard C++ program includes header files, namespace declarations, and a main function where execution begins.

#include <iostream>
using namespace std;

int main() {
    cout << "Hello, Object-Oriented World!" << endl;
    return 0;
}

• #include <iostream> allows input/output operations.
• using namespace std; tells the compiler to use the standard namespace.
• main() is the mandatory entry point of the program.

Control structures dictate the flow of the program logic. They are divided into decision-making and looping structures.

• Selection / Decision Making: if, if-else, switch. Used to branch execution based on conditions.
• Iteration / Looping: for, while, do-while. Used to repeat blocks of code until a condition is met.

For the practical portion of the exam, you must be comfortable writing these standard logic algorithms in C++:

1. Prime Number Identification

#include <iostream>
using namespace std;

int main() {
    int n, i, flag = 0;
    cout << "Enter a positive integer: ";
    cin >> n;
    if (n == 0 || n == 1) flag = 1;
    for (i = 2; i <= n / 2; ++i) {
        if (n % i == 0) {
            flag = 1;
            break;
        }
    }
    if (flag == 0)
        cout << n << " is a prime number.";
    else
        cout << n << " is not a prime number.";
    return 0;
}

2. Fibonacci Sequence Generator

#include <iostream>
using namespace std;

int main() {
    int n, t1 = 0, t2 = 1, nextTerm = 0;
    cout << "Enter the number of terms: ";
    cin >> n;
    cout << "Fibonacci Series: ";
    for (int i = 1; i <= n; ++i) {
        if(i == 1) { cout << t1 << " "; continue; }
        if(i == 2) { cout << t2 << " "; continue; }
        nextTerm = t1 + t2;
        t1 = t2;
        t2 = nextTerm;
        cout << nextTerm << " ";
    }
    return 0;
}

3. Armstrong Number Validation

#include <iostream>
using namespace std;

int main() {
    int num, originalNum, remainder, result = 0;
    cout << "Enter a three-digit integer: ";
    cin >> num;
    originalNum = num;
    while (originalNum != 0) {
        remainder = originalNum % 10;
        result += remainder * remainder * remainder;
        originalNum /= 10;
    }
    if (result == num)
        cout << num << " is an Armstrong number.";
    else
        cout << num << " is not an Armstrong number.";
    return 0;
}

Access specifiers define how the members (attributes and methods) of a class can be accessed. In C++, there are three main access modifiers used to implement Data Hiding and Encapsulation:

#include <iostream>
using namespace std;

class Base {
  private:
    int x; // Only accessible within Base
  protected:
    int y; // Accessible within Base and derived classes
  public:
    int z; // Accessible everywhere
};