// Comment to end of line
/* Multi-line comment */
#include <stdio.h> // 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
""")255, 0377, 0xff // Integers (decimal, octal, hex)
123.0 // double (real) numbers
'a' // Character (literal)
'\\n', '\\\\', '\\'', '\\"' // Newline, backslash, single quote, double quote
\"string\\n\" // Array of characters ending with newline and \\0
\"hello\" \"world\" // Concatenated strings
""")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 =
0xffffffffUL; // 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}; )
char s[]="hello"; // String (6 elements including '\\0')
typedef char* String; // Typedef: String is an alias for char*
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 intint x; // Auto (memory exists only while in scope)
static int x; // Global lifetime even if local scope
extern int x; // Information only, declared elsewherex=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
}
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 the bottom of while, do, or for loop
return x; // Return x from function to caller
""")int f(int x, int y); // 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)
int f(); // Default return type is int
inline void f(); // Optimize for speed
void 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
""")int main() { statements... } // or
int main(int argc, char* argv[]) { statements... }
// argv is an array of argc strings from the command line.
// By convention, main returns status 0 if successful, 1 or higher for errors.
// Function parameters and return values may be of any type.
// A function must either be declared or defined before it is used.
It may be declared first and defined later.
// Every program consists of a set of global variable declarations and a set of
function definitions (possibly in separate files), one of which must be:
###// Overloading functions with different parameters
void foo(int x);
void foo(double x);
// Operator overloading
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)// Operators except :: . .* ?: may be overloaded.
// Precedence order is not affected.
// New operators may not be created.
T::X // Name X defined in class T
N::X // Name X defined in namespace N
::X // Global name X
t.x // Member x of struct or class t
p->x // Member x of struct or class pointed to by p
a[i] // i'th element of array a
f(x, y) // Call to function f with arguments x and y
T(x, y) // Object of class T initialized with x and y
x++ // Add 1 to x, evaluates to original x (postfix)
x-- // Subtract 1 from x, evaluates to original x
typeid(x) // Type of x
typeid(T) // Equals typeid(x) if x is a T
dynamic_cast<T>(x) // Converts x to a T, checked at run time.
static_cast<T>(x) // Converts x to a T, not checked
reinterpret_cast<T>(x) // Interpret bits of x as a T
const_cast<T>(x) // Converts x to same type T but not const
sizeof x // Number of bytes used to represent object x
sizeof(T) // Number of bytes to represent type T
++x // Add 1 to x, evaluates to new value (prefix)
--x // Subtract 1 from x, evaluates to new value
~x // Bitwise complement of x
!x // true if x is 0, else false (1 or 0 in C)
-x // Unary minus
+x // Unary plus (default)
&x // Address of x
*p // Contents of address p (*&x equals x)
new T // Address of newly allocated T object
new T(x, y) // Address of a T initialized with x, y
new T[x] // Address of allocated n-element array of T
delete p // Destroy and free object at address p
delete[] p // Destroy and free array of objects at p
(T) x // Convert x to T (obsolete, use static_cast<T>(x))
x * y // Multiply
x / y // Divide (integers round toward 0)
x % y // Modulo (result has sign of x)
x + y // Add, or &x[y]
x - y // Subtract, or number of elements from *x to *y
x << y // x shifted y bits to the left (x * pow(2, y))
x >> y // x shifted y bits to the right (x / pow(2, y))
x < y // Less than
x <= y // Less than or equal to
x > y // Greater than
x >= y // Greater than or equal to
x & y // Bitwise and (3 & 6 is 2)
x ^ y // Bitwise exclusive or (3 ^ 6 is 5)
x | y // Bitwise or (3 | 6 is 7)
x && y // x and then y (evaluates y only if x (not 0))
x || y // x or else y (evaluates y only if x is false (0))
x = y // Assign y to x, returns new value of x
x += y // x = x + y, also -= *= /= <<= >>= &= |= ^=
x ? y : z // y if x is true (nonzero), else z
throw x // Throw exception, aborts if not caught
x , y // evaluates x and y, returns y (seldom used))
#include <new> // Include new (std namespace)
int *x = new int; // Allocate memory for an int on the heap
int *y = new int[10]; // Allocate memory for an array of 10 ints on the heap
*x = 5; // Assign value to allocated memory
y[0] = 10; // Assign value to first element of allocated array
delete x; // Deallocate memory for single int
delete[] y; // Deallocate memory for array of ints
int *z = new (nothrow) int; // Allocate memory, return NULL if allocation fails
if (z == NULL) {
// Handle allocation failure
}
If you find anything missing or wrong please feel free to add a pull request
Feel free to suggest or write a github issue.
--- Inspired from this guy : https://github.com/mortennobel/cpp-cheatsheet