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Datatypes in C++

Hey there! In this guide, we'll explore the different data types available in C++. Understanding data types is crucial for writing efficient and clear C++ code. Let's dive in!

  • In C++, variables are containers that hold data and are defined by specifying a type followed by the variable name.
  • Variables must be declared before use and can hold various data types.

1. Declaring Variables in C++​

  • To declare a variable in C++, you specify its type, followed by the variable's name.
int age;
double salary;
char grade;

2. Initializing Variables in C++​

  • Variables can be initialized with a value at the time of declaration.
int age = 25;
double salary = 45000.50;
char grade = 'A';

3. Types of Variables in C++​

a. Integer Variables (int)​

  • Holds whole numbers, both positive and negative.
int x = 10;
int y = -20;

b. Floating-Point Variables (float, double)​

  • Represents real numbers, with float using less precision than double.
float pi = 3.14f;
double gravity = 9.81;

c. Character Variables (char)​

  • Stores a single character enclosed in single quotes.
char initial = 'A';

d. Boolean Variables (bool)​

  • Holds either true or false values.
bool is_sunny = true;
bool is_raining = false;

e. String Variables (std::string)​

my_list = [1, 2, 3]
my_tuple = tuple(my_list)
print(my_tuple)   # Output: (1, 2, 3)
print(type(my_tuple)) # Output: <class 'tuple'>

4. Variable Scope​

  • The scope of a variable refers to the region of the program where the variable is accessible.
  • Local Variables: Declared inside functions or blocks, only accessible within that block.
  • Global Variables: Declared outside all functions and accessible from any part of the program.

a. Local Variable Example:​

void myFunction() {
    int localVar = 10;  // Only accessible inside myFunction
}

b. Global Variable Example:​

int globalVar = 20;  // Accessible throughout the program

void myFunction() {
    globalVar = 30;   // Modifying globalVar
}

5. Constant Variables​

  • Variables declared as const cannot be modified after initialization.
const int MAX_AGE = 100;

6. Type Conversion​

C++ allows conversion between data types either implicitly or explicitly (using type casting).

a. Implicit Type Conversion​

  • C++ automatically converts one type to another when necessary.
int x = 10;
double y = x;  // Implicit conversion from int to double

b. Explicit Type Conversion (Casting)​

  • You can explicitly convert a variable's type using type casting.
double pi = 3.14;
int int_pi = (int)pi;  // Cast double to int

7. Dynamic Variables​

  • Variables that are allocated memory during runtime using pointers and dynamic memory allocation (new and delete).
int* ptr = new int;  // Dynamically allocate memory for an integer
*ptr = 5;
delete ptr;         // Free the allocated memory

Variables are a crucial part of any C++ program, and understanding how to use them effectively is key to writing efficient C++ code.