Lecture Notes: Introduction to Programming by Striver

Introduction

• Speaker: Striver
• Platform: YouTube
• Focus: Interview preparation with Data Structures and Algorithms (DSA)
• **Resources: ** Striver's SD Sheet (for experienced), Striver's A to Z DSA (for beginners)

Resources

• Striver's SD Sheet:
  • Curated list of 191 DSA problems
  • Requires basic DSA knowledge
• **Striver's A to Z DSA Sheet: **
  • 455 steps with problem links and video explanations
  • Covers basic to advanced DSA topics

Social Media

• Follow Striver on: LinkedIn, Twitter, Instagram, Telegram

Programming Languages

• C++, Java, Python, JavaScript: Choose one and master it
• Video Sequence: Covers basic, then detailed topics for each language

C++ Basics

Skeleton of a C++ Code

• #include <iostream> using namespace std; int main() { // Code return 0; }

Input & Output

• Use #include <iostream> for I/O operations
• Example to print a name: cout << "Striver" << endl; ``

Managing Namespaces

• Use std:: for using I/O functions like cout and cin
• To avoid typing std:: each time, use using namespace std;

Data Types

• Integer Types: int, long, long long
• Floating-Point: float, double
• Strings and Characters:
  • char (single character)
  • string (sequence of characters)
• Input/Output: int x; cin >> x; cout << x << endl; ``

Including All Libraries

• #include <bits/stdc++.h> – Includes all standard libraries

Conditional Statements

If-Else Structure

• Example: Check if age is an adult int age; cin >> age; if (age >= 18) { cout << "You are an adult"; } else { cout << "You are not an adult"; }

Switch Case

• For fixed multiple choice values switch(variable) { case 1: // code break; case 2: // code break; ... default: // code }

Arrays and Strings

Arrays

• 1D Array: int arr[5]; for (int i = 0; i < 5; i++) { cin >> arr[i]; } for (int i = 0; i < 5; i++) { cout << arr[i] << " "; }
• 2D Array: int arr[3][5]; // 3 rows, 5 columns

Strings

• Access and modify characters by index
• Example: string s = "Striver"; cout << s[0] << endl; // Prints 'S' s[0] = 'Z'; cout << s[0] << endl; // Prints 'Z'

Loops

For Loop

• Syntax: for (int i = 0; i < n; i++) { // code }
• Example: for (int i = 1; i <= 10; i++) { cout << i << endl; }

While Loop

• Syntax: int i = 0; while (i < n) { // code i++; }

Do-While Loop

• Executes at least once int i = 0; do { // code i++; } while(i < n);

Functions

Basics

• Purpose: Reusability, Readability, and Modularity
• Syntax: return_type function_name(parameters) { // Code return value; }

Types

• Void Functions: Do not return a value void printName() { cout << "Striver" << endl; }
• Parameterized Functions: Accept parameters void printName(string name) { cout << name << endl; }
• Return Functions: Return a value int add(int num1, int num2) { return num1 + num2; }

Pass by Value vs Reference

• Pass by Value: Copy is passed; changes not reflected outside function void changeValue(int a) { a = 5; // Affect local 'a' only }
• Pass by Reference: Original value is passed; changes reflected outside void changeValue(int &a) { a = 5; // Affect original variable }
• Arrays: Always passed by reference void modifyArray(int arr[], int size) { arr[0] = 10; // Original array modified }

Final Points

• Interactive Sessions: Video includes Q&A sessions
• Practice: Follow the curated sheets for hands-on practice

Conclusion

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