IF:

	The if statement is very similar to the C if statement. 

	if ( expression )
	{
	  statement(s)
	else
	  statement(s)
	}

	The "else" is optional, and the braces are always required.
	The differences between the C-language if-statement and RLaB's
	are due to the special demands of an interactive language.

	Examples:

	if ( init ) 
        {
	  mass = 10.0;
	  inertia = 3*mass/length^3;
	  init = 0;
	}

	if(class(data) == "string") 
	{
	  fprintf(file, data);
	else
	  write(file, data);
	}

	if( class(v) != "matrix" ) { error(); }

	Note the semicolon ( `;' ) in the last if statement. Each
	statement must be properly terminated. The three possible
	terminators are: `\n' `;' and `?'. This explains why
	statements inside `{' `}' must be terminated with a `;' when
	there is no newline.The if statement could also look like:

	if( class(v) != "vector" ) { error()? }

	if( class(v) != "vector" ) { error()
        }

	if( class(v) != "vector" ) { 
	  error()
        }

	if( class(v) != "vector" ) 
	{ 
	  error()
        }

	At present there is no explicit elseif statement. However the
	else if behavior can be implemented as it is in C (although
	RLaB's syntax is somewhat clumsier). For example:

	if( test1 ) 
	{
	  x = a;
	else if( test2 ) {
	  x = b;
	else if( test3 ) {
	  x = c;
	else 
	  error();
	}}}
