C++ QUICK REFERENCE

C++ QUICK REFERENCE

PREPROCESSOR

// Comment to end of line

/* Multi-line comment */

#include // Insert standard header file

#include "myfile.h" // Insert file in current directory

#define X some text // Replace X with some text

#define F(a,b) a+b // Replace F(1,2) with 1+2

#define X \

some text // Line continuation

#undef X // Remove definition

#if defined(X) // Condional compilation (#ifdef X)

#else // Optional (#ifndef X or #if !defined(X))

#endif // Required after #if, #ifdef

LITERALS

255, 0377, 0xff // Integers (decimal, octal, hex)

2147483647L, 0x7fffffffl // Long (32-bit) integers

123.0, 1.23e2 // double (real) numbers

'a', '\141', '\x61' // Character (literal, octal, hex)

'\n', '\\', '\'', '\"' // Newline, backslash, single quote, double

quote

"string\n" // Array of characters ending with newline and

\0

"hello" "world" // Concatenated strings

true, false // bool constants 1 and 0

DECLARATIONS

int x; // Declare x to be an integer (value undefined)

int x=255; // Declare and initialize x to 255

short s; long l; // Usually 16 or 32 bit integer (int may be

either)

char c='a'; // Usually 8 bit character

unsigned char u=255; signed char s=-1; // char might be either

unsigned long x=0xffffffffL; // short, int, long are signed

float f; double d; // Single or double precision real (never

unsigned)

bool b=true; // true or false, may also use int (1 or 0)

int a, b, c; // Multiple declarations

int a[10]; // Array of 10 ints (a[0] through a[9])

int a[]={0,1,2}; // Initialized array (or a[3]={0,1,2}; )

int a[2][3]={{1,2,3},{4,5,6}}; // Array of array of ints

char s[]="hello"; // String (6 elements including '\0')

int* p; // p is a pointer to (address of) int

char* s="hello"; // s points to unnamed array containing "hello"

void* p=NULL; // Address of untyped memory (NULL is 0)

int& r=x; // r is a reference to (alias of) int x

enum weekend {SAT,SUN}; // weekend is a type with values SAT and SUN

enum weekend day; // day is a variable of type weekend

enum weekend {SAT=0,SUN=1}; // Explicit representation as int

enum {SAT,SUN} day; // Anonymous enum

typedef String char*; // String s; means char* s;

const int c=3; // Constants must be initialized, cannot assign

to

const int* p=a; // Contents of p (elements of a) are constant

int* const p=a; // p (but not contents) are constant

const int* const p=a; // Both p and its contents are constant

const int& cr=x; // cr cannot be assigned to change x

STORAGE CLASSES

int x; // Auto (memory exists only while in scope)

static int x; // Global lifetime even if local scope

extern int x; // Information only, declared elsewhere

STATEMENTS

x=y; // Every expression is a statement

int x; // Declarations are statements

; // Empty statement

{ // A block is a single statement

int x; // Scope of x is from declaration to end of

block

a; // In C, declarations must precede statements

}

if (x) a; // If x is true (not 0), evaluate a

else if (y) b; // If not x and y (optional, may be repeated)

else c; // If not x and not y (optional)

while (x) a; // Repeat 0 or more times while x is true

for (x; y; z) a; // Equivalent to: x; while(y) {a; z;}

do a; while (x); // Equivalent to: a; while(x) a;

switch (x) { // x must be int

case X1: a; // If x == X1 (must be a const), jump here

case X2: b; // Else if x == X2, jump here

default: c; // Else jump here (optional)

}

break; // Jump out of while, do, or for loop, or switch

continue; // Jump to bottom of while, do, or for loop

return x; // Return x from function to caller

try { a; }

catch (T t) { b; } // If a throws a T, then jump here

catch (...) { c; } // If a throws something else, jump here

FUNCTIONS

int f(int x, int); // f is a function taking 2 ints and returning

int

void f(); // f is a procedure taking no arguments

void f(int a=0); // f() is equivalent to f(0)

f(); // Default return type is int

inline f(); // Optimize for speed

f() { statements; } // Function definition (must be global)

T operator+(T x, T y); // a+b (if type T) calls operator+(a, b)

T operator-(T x); // -a calls function operator-(a)

T operator++(int); // postfix ++ or -- (parameter ignored)

extern "C" {void f();} // f() was compiled in C