Basic Data Types
C++ has several fundamental data types for storing different kinds of values.
Example
#include <iostream>
using namespace std;
int main() {
// Integer types
int age = 25;
short small = 100;
long big = 1000000L;
long long veryBig = 9000000000LL;
// Floating point
float price = 9.99f;
double pi = 3.14159265;
// Character and Boolean
char letter = 'A';
bool isActive = true;
// Auto type deduction (C++11)
auto count = 42; // int
auto name = "Alice"; // const char*
// Constants
const double TAX_RATE = 0.08;
// TAX_RATE = 0.10; // Error!
return 0;
}Type Casting and sizeof
C++ supports both implicit and explicit type conversions. Use sizeof to check the size of types.
Example
// Implicit casting (widening)
int x = 10;
double y = x; // 10.0
// Explicit casting (narrowing)
double pi = 3.14;
int rounded = (int)pi; // C-style cast: 3
int rounded2 = static_cast<int>(pi); // C++ style: 3
// sizeof operator
cout << sizeof(int) << endl; // 4 bytes
cout << sizeof(double) << endl; // 8 bytes
cout << sizeof(char) << endl; // 1 byte
cout << sizeof(bool) << endl; // 1 byte