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

if (condition) {
    // code
} else if (condition) {
    // code
} else {
    // code
}

• 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

• Subscribe: Encourages to subscribe for regular updates
• Follow: Updates on social media for new content