C

#include<stdio.h>
main(){printf("Hello, World\n");}

// Types
typedef int I;
typedef double F;
typedef unsigned char C,*S;
typedef long L;
typedef void V;

// Arithmetic
#define MON(m,n) ((m)>(n)?(m)-(n):0)
#define PD(m,n)  ((m)>(n)?(m)-(n):(n)-(m))
#define MAX(m,n) ((m)>(n)?(m):(n))
#define MIN(m,n) ((m)<(n)?(m):(n))
#define SGN(n)   ((0<(n))-(0>(n)))

// Return, For, While, Conditional
#define R         return
#define F(e...)   for(e)
#define W(c...)   while(c)
#define C(c,t...) if(c){t;}else

// sequence
#define I(m,e...) {I i=0,_i=(m);F(;i<_i;++i){e;}}
#define J(n,e...) {I j=0,_j=(n);F(;j<_j;++j){e;}}
#define K(n,e...) {I k=0,_k=(n);F(;k<_k;++k){e;}}

// I/O
#include<stdio.h>
#define GC()    getchar()
#define PC()    putchar()
#define SF(e...) scanf(e)
#define PF(e...) printf(e)

// Assert, Predicate, Error
#define A(e...)   {if(!(e))R 0;} 
#define P(c,e...) {if(c)R(e);}
#define E(c,e...) {if(c)R P("ERROR: %s\n",(e)),(S)0;}

Type   Format b> Range>
char   %c      8 schar|uchar
schar  %c|%hhi 8 +-127
uchar  %c|%hhu 8 0,255
short  %hi    16 +-32767
ushort %hu    16 0,65545
int    %i|%d  16 +-32767
uint   %u     16 0,4294967295
long   %li    32 +-2147483647
ulong  %lu    32 0,4294967295
llong  %lli   64 +-9223372036854775807
ullong %llu   64 0,18446744073709551615
float  %f|%lf 32 +-3.4e38
double %f|%lf 64 +-1.7e308

Escape Sequences
\a 07 bell
\b 08 bspace
\f 0c ffeed
\n 0a nline
\r 0d return
\t 09 htab
\v 0b vtab
\\ 5c bslash
\' 27 squote
\" 22 dquote
\? 3f qmark
\ooo  oct
\xhh  hex

// Function Prototype
// Tr type returned
// Tx type of x
// Ty type of y
// Tz type of z
// Tr f(Tx,Ty,Tz)  elide parameter names in prototype
// Functions get arguments "By Value"
I f(I,I);
I f(I x, I y){x=x+y; R x;}
main(){
//puts "a=3 gives 1\n" to stdout
I b,a=3;
b=f(a, 5);
if(a==3){printf("a=3 gives 1\n");}
if(a==7){printf("a=7 gives 1\n");}
}

Note (S)0 is a null pointer, and ',' is being used as the comma operator 
because it discards the side effect of O and returns (S)0 which is a null 
pointer (of the char type, if you're a compiler and happen to be interested in 
that sort of thing).

Sources
http://en.cppreference.com/w/d
http://www.gnu.org/software/gnu-c-manual/gnu-c-manual.html
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf