COSC 1315 Fundamentals of Programming

COSC 1315 Fundamentals of Programming

C/C++ Syntax

Character set

  a .. z
  A .. Z
  0 .. 9
  ! # % ^ & * ( ) - _
  + = ~ [ } \ | ; : '
  " { } , . < > / ?

Comments
Any sequence that begins with /* and ends with */. Or starts with // to the end of the line. C++ ignores anything within comments. Comments may not be nested.
Tokens
The lexical structure of a C++ programs is divided into 5 classes
1. Operators
```
!	%	^	&	*
-	+	 = 	~	|
.	<	>	/	? :
->	++	--	<<	>>
<=	>=	==	!=	&&
||	+=	-=	*=	/=
%=	<<=	>>=	&=	^=
|=	->	::
```
2. Separators
```
 ( ) [ ] { } , ; :
```
  and a blank.
3. Identifiers
  A sequence of letters and digits and underscores, which is not a reserved word. Must start with a letter. Note case is important. Identifiers may either be variable, structure, class or function names.
4. Reserved words
  asm auto break bool case catch char class
  const const_class continue default delete do double
  dynamic_cast else enum explicit extern
  false float for friend goto if inline int long mutable
  namespace new operator private protected public
  register return short signed sizeof static static_cast struct
  switch template this throw true try typedef
  typeid typename union unsigned using virtual void
  volatile wchar_t while
5. Constants
  1. Integer
    whole numbers specified in the program.
  2. Octal
    preceded with 0 as in 077
  3. Hex
    preceded with 0x as in 0xa7
  4. Floating point
```
1.0
1.0e3
2e+9
```
  5. Character
    enclosed in single quotes. special sequence with \
```
\n  newline
\t  horizontal tab
\v  vertical tab
\b  backspace
\r  carriage return
\f  formfeed
```
  6. String
    constants are enclosed in double quotes like "hello".
A C++ program
is made up of expressions and statements. Statements are terminated with a semicolon (;) or compound statements are enclosed in { }.
1. Expression
```
   x++
```
2. Simple statement
```
   x++:
```
3. Compound statement
```
{
    x++;
    y--;
}
```
C++ Functions
The general format of a C++ function is:
```
 function_name (formal argument list)
 {
  body of function
 }
```
Every C++ program MUST have at least one function called main. This function receives control from the Operating system and is executed first. The simplest program given in most C++ texts is the ubiquitous Hello World.
```
#include <iostream>

using namespace std;

void main()
{
  cout << "Hello World" << endl;
}
```