data-type.cpp

#include <iostream>
#include <string> // Recommended for explicit string usage
using namespace std;

int main() {
    // ===================================================
    // 1. STANDARD DATA TYPES (Explicit Type Declaration)
    // ===================================================
    // Declaring variables by explicitly specifying their data type.

    int myNum = 5;               // Integer: stores whole numbers (4 bytes)
    float myFloatNum = 5.99f;    // Float: stores fractional numbers, up to 7 decimal digits (4 bytes)
    double myDoubleNum = 9.98;   // Double: stores fractional numbers, up to 15 decimal digits (8 bytes)
    char myLetter = 'D';         // Character: stores a single character/letter in single quotes (1 byte)
    bool myBoolean = true;       // Boolean: stores true (1) or false (0) (1 byte)
    string myText = "Hello";     // String: stores text wrapped in double quotes

    cout << "=== STANDARD DATA TYPES ===" << endl;
    cout << "Integer (int)    : " << myNum << endl;
    cout << "Float (float)    : " << myFloatNum << endl;
    cout << "Double (double)  : " << myDoubleNum << endl;
    cout << "Character (char) : " << myLetter << endl;
    cout << "Boolean (bool)   : " << myBoolean << " (true prints as 1)" << endl;
    cout << "String (string)  : " << myText << endl;

    // ===================================================
    // 2. AUTOMATIC TYPE DEDUCTION (`auto` Keyword)
    // ===================================================
    // Introduced in C++11. The compiler automatically deduces the type 
    // based on the assigned literal value.

    auto autoNum    = 5;               // Deduced as: int
    auto autoFloat  = 5.99f;           // Deduced as: float (note the 'f' suffix)
    auto autoDouble = 9.98;            // Deduced as: double (default for decimals)
    auto autoLetter = 'D';             // Deduced as: char
    auto autoBool   = true;            // Deduced as: bool
    auto autoString = string("Hello"); // Deduced as: std::string

    cout << "\n=== AUTO TYPE DEDUCTION ===" << endl;
    cout << "autoNum    (int)    : " << autoNum << endl;
    cout << "autoFloat  (float)  : " << autoFloat << endl;
    cout << "autoDouble (double) : " << autoDouble << endl;
    cout << "autoLetter (char)   : " << autoLetter << endl;
    cout << "autoBool   (bool)   : " << autoBool << endl;
    cout << "autoString (string) : " << autoString << endl;

    return 0;
}