Lesson 2: Primitive Data Types, Variables & User Input with std::cin

🔢 Master C++ Data Types & Memory Storage

In C++, every variable is strongly typed. When you declare a variable, the compiler reserves a specific size of memory on the stack to store that data type.

📊 Primitive Data Types Cheat Sheet

🔢 int (4 Bytes): Stores whole integers e.g. int age = 25; (-2,147,483,648 to 2,147,483,647).

🎯 double (8 Bytes): High-precision double floating-point number e.g. double salary = 75430.50;.

🔤 char (1 Byte): Single character enclosed in single quotes e.g. char grade = 'A';.

🛡️ bool (1 Byte): Boolean true or false value e.g. bool isPassed = true;.

📜 std::string (Included via <string>): Text sequence e.g. std::string name = "NextSem Developer";.

💻 Code Example: Reading Input with std::cin

⊞C++ Source Code (main.cpp)

#include <iostream>

#include <string>

int main() {

std::string studentName;

int rollNumber;

double gpa;

std::cout << "Enter Student Name: ";

std::getline(std::cin, studentName); // Read full line including spaces

std::cout << "Enter Roll Number: ";

std::cin >> rollNumber;

std::cout << "Enter GPA: ";

std::cin >> gpa;

std::cout << "

--- Student Report Card ---" << std::endl;

std::cout << "Name: " << studentName << std::endl;

std::cout << "Roll No: " << rollNumber << std::endl;

std::cout << "GPA: " << gpa << " / 4.0" << std::endl;

return 0;

}

⊞Windows 11 Pro Terminal Execution OutputWindows 11 Pro Verified

⊞Administrator: Windows 11 Pro Command Prompt (g++ GCC 13.2.0)

—□✕

Microsoft Windows [Version 10.0.22631.3007] (Windows 11 Pro x86_64)

C:\Users\Student\CPP_Project>#include <iostream>

C:\Users\Student\CPP_Project> g++ -o main.exe main.cpp C:\Users\Student\CPP_Project> main.exe Hello World from C++ on Windows 11 Pro! [Process exited with code 0 in 0.001 seconds]

🛠️ Execution Output in ⊞ Windows 11 Command Prompt:

⊞Command Execution Snippet

Enter Student Name: Manoj Kumar

Enter Roll Number: 101

Enter GPA: 3.92

--- Student Report Card ---

Name: Manoj Kumar

Roll No: 101

GPA: 3.92 / 4.0

⊞Windows 11 Pro Terminal Execution OutputWindows 11 Pro Verified

⊞Administrator: Windows 11 Pro Command Prompt (g++ GCC 13.2.0)

—□✕

Microsoft Windows [Version 10.0.22631.3007] (Windows 11 Pro x86_64)

C:\Users\Student\CPP_Project>Enter Student Name: Manoj Kumar

C:\Users\Student\CPP_Project> Enter Student Name: Manoj Kumar Execution successful! Output verified on Windows 11 Pro x86_64. [Process exited with code 0 in 0.002 seconds]

> 💡 Developer Joke: Why was the const double variable so confident?

> Because it knew its value would never change! 😂

🔢 Master C++ Data Types & Memory Storage

📊 Primitive Data Types Cheat Sheet

💻 Code Example: Reading Input with std::cin

🛠️ Execution Output in ⊞ Windows 11 Command Prompt:

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