C++ Coding Style Rules

• Align all curly braces vertically to allow easy visual matching.
• Use four (4) spaces for each indentation.
• Indent all statements contained within compound statements (if, for, while, {}, etc).
• Use meaningful names for variables, parameters, subprograms, and classes. (You may use simple names like i, c, s, f, or p for general integers, characters, strings, floats, or pointers respectively.)
• Use the following (Java-like) conventions for identifiers:

  Identifier	Convention	Examples
  class names	capitalize first word, capitalize all other words (no underscores)	Circle, FilledCircle, ShadedFilledCircle
  class member names	lowercase first word, capitalize all other words (no underscores)	draw(), drawLine(), centerX, centerY, radius
  function names	lowercase first word, capitalize all other words (no underscores)	findIndex(), factorial(), toLowerCase(), isUpperCase()
  named constants	all caps, use underscores to separate words	PI, MAX_BUFFER_SIZE

• Use whitespace around every binary operator (e.g, x + y instead of x+y) and around function arguments (e.g, put( x, y ) instead of put(x,y)).
• Keep subprograms simple. At most five simple statements or one compound statement and two simple statements.
• Keep compound statements simple. At most three simple statements per statement list.
• Avoid over parenthesization, e.g, return x + 1; instead of return (x + 1);
• Comment each function, each class, and each class member (describing it's purpose) using a form similar to the example at the very end. (Note I only commented a few members to avoid cluttering up the Class example.)

Examples of Subroutines

a function

int factorial( int n )
{
    if ( n <= 0 )
        return 1;
    else
        return n * factorial( n - 1 );
}

a procedure

void print( int n )
{
    for ( int i = 0; i < n; i++ )
        cout << n << ' ';
    cout << endl;
}

an operator

ostream & operator << ( ostream & out, Circle c )
{
    return out << "Circle is " << c.radius;
}

the main routine and it's arguments

#include < iostream.h>

int main()
{
    while ( true )
    {
        cout << "this is the class that never ends,\n";
        cout << "yes it goes on and on my friend,\n";
        cout << "some students started taking it not knowing what it was,\n";
        cout << "and they'll continue taking it forever just because\n";
    }
    return 0;
}

Examples of statments

simple if/else

     if ( x < y )
         y = 0;
     else
         x = 1;

cascaded if/else

     if ( var1 < var2 )
     {    
         var1 = ...;
         var2 = ...;
           ...
     }
     else if ( var1 == var2 )
     {
         var1 = ...;
         var2 = ...;
         ...
     }
     else
     {        
         var1 = ...;
         var2 = ...;
           ...
     }
  

switch statement

     switch ( factorial( i ) )
     {
         case 1:
         case 3:
         case 5:
             cout << "It's odd!\n";
             break;
         case 2:
         case 4:
         case 6:
             cout << "It's even!\n";
             break;
         default:
             cout << "It's less than 1 or greater than 6!\n";
             break;
      }

loop statements

     for ( int i = 0; i < MAX_VAL; i++ )
     {
         ...
         ...
     }

     while ( !cin.eof() )
     {
         cin.get( ch );
         cout.put( ch );
     }

     do // read the first line (including the newline) only
     {
         cin.get( ch );
         cout.put( ch );
     } while ( ch != '\n' );
  

Examples of Class Definitions

     /*
        classes Shape, Point, and Rectangle define a class hierarchy
        for geometrical shapes.
     */
     class Shape
     {
     public:
         // draws this shape on the display
         virtual void draw() = 0;
         // inverts this shape along a horizontal line
         virtual void flip() = 0;
         // rotates this shape by number of degrees specified by angle
         virtual void rotate( int angle ) = 0;
     };

     class Point
     {
     public:
         // the origin of this point in 2-D space
         int x, y;
         Point( int newX, int newY ) 
             : x( newX ), y( newY ) 
         {
         }
     };
    
     class Rectangle
         : public Shape
     {
     private:
         Point tl;
         Point br;
         int angle;
     
     protected:
         ...

     public:
         Rectangle();
         virtual ~Rectangle();
         ...
         void draw();
         void flip();
         void rotate( int angle );
         float area();
     };

Examples of REALLY BAD commenting

     /*
        This is a class defintion for Shape.
     */
     class Shape
     {
     public:
         // These are pure virtual functions
         // draws shape
         virtual void draw() = 0;
         // flips shape
         virtual void flip() = 0;
         // rotates shape
         virtual void rotate( int angle ) = 0;
     }; // end of Shape

     // A Point class
     class Point
     {
     public:
         // Two integers
         int x, y;
         // a constructor
         Point( int newX, int newY ) 
             : x( newX ), y( newY )  // construct x and y
         {
            // do nothing here
         } // end of Point
     };
    
     class Rectangle
         : public Shape // Rectangle is publically derived from Shape
     {
     private: // some private members
         Point tl;
         Point br;
         int angle;
     
     protected: // some protected members
         ...

     public: // the public members
         Rectangle(); // constructor
         virtual ~Rectangle(); // destructor
         ...
         void draw(); // some member functions
         void flip()
         {
            if (x != y)
            {
                swap(x,y); // swap the values of x and y 
                flip(); // flip again
            } // end if
         } // end flip()
         void rotate( int angle );
         float area();
     }; // end Rectangle