Learn C++ Programming

Primitive Data Types

Type	Size (bytes)	Range	Example
int	4	-2,147,483,648 to 2,147,483,647	int age = 25;
float	4	±3.4e±38 (~7 digits)	float pi = 3.14f;
double	8	±1.7e±308 (~15 digits)	double precise = 3.1415926535;
char	1	-128 to 127 or 0 to 255	char grade = 'A';
bool	1	true or false	bool isValid = true;
void	N/A	N/A	void printMessage();

short int smallNum;     // At least 2 bytes
long int bigNum;        // At least 4 bytes
long long int hugeNum;  // At least 8 bytes

signed int normal;     // Can be positive/negative (default)
unsigned int positive;  // Only positive values

int numbers[5];          // Declaration
float temps[] = {36.5, 37.0};  // Initialization

int num = 10;
int* ptr = &num;  // Pointer to num

int original = 5;
int& ref = original;  // Reference to original

struct Person {
  string name;
  int age;
  float height;
};

Person p1;
p1.name = "Alice";

class Rectangle {
  private:
    int width, height;
  public:
    void setDimensions(int w, int h) {
      width = w;
      height = h;
    }
};

int num = 10;
double d = num;  // Automatically converted

double pi = 3.14159;
int approx = (int)pi;  // C-style cast
int precise = static_cast<int>(pi);  // C++ cast

typedef unsigned long ulong;  // Traditional
using Celsius = float;        // Modern (C++11)

ulong bigNumber;
Celsius currentTemp = 23.5;