// OUTSIDE SCOPE: variable declaration
// NOTE: set extern to make visible in all files
int x; // integer, 4 bytes
char c; // character, 1 byte
char c_arr[6]; // character array of size 6 (string)
float z; // floating point, 4 bytes
double z_double; // floating point, 8 bytes
bool t; // boolean (true or false), 1 byte
// INSIDE SCOPE: variable definition
int x;
// variable initialisation
x = 6; // 6
c = 65; // A (ASCII)
z = 1.05; // 1.05
t = true; // 1
// or scientific notation
z_double = 10e4; // 100000
// variable definition and initialisation
char c = 'S';
// character array with undefined size
char c_arr[] = "String";
// multiple variable definition
int x, y;
// multiple variable initialisation
x = y = 6; // 6, 6
// multiple variable definition and initialisation
int x = 6, y = 6;
// typedef to create alias
typedef int myint;
myint x = 10, y = 5, z = -20;
cout << x << ", " << y << ", " << z << endl;
// 10, 5, -20
// type modifiers
unsigned int unsigned_int; // 4 bytes, 0 to 4294967295
signed int signed_int; // 4 bytes, -2147483648 to 2147483647
short int short_int; // 2 bytes, -32768 to 32767
long int long_int; // 8 bytes, -2147483648 to 2147483647
long long int long_long_int; // 8 bytes, -(2^63) to (2^63)-1
// storage classes
register int register_int; // make it possible to store local variable in register (instead of RAM)
static int static_int; // keep local variable in existence during execution
extern int extern_int; // global variable visible to all program files