Synopsis: if (condition) then_part [ else else_part ]

Depending on condition only one of the code branches then_part and else_part is executed. The else_part is optional and may be omitted. Both then_part and else_part may either be single statements or a sequence of statements enclosed in curly brackets, i.e. a block. The then_part is executed if and only if condition evaluates to true, the else_part otherwise. It is an error if condition evaluates to something other than true or false.

{
    integer a = 10;

    if ( a > 10 )
	y2milestone("a is greater than 10");
    else
    {
	// Multiple statements require a block...
	
	y2milestone("a is less than or equal to 10");
	a = a * 10;
    }
}

{
    list &string& new_list = ["a", "new", "string"];

    if (contains(new_list, "test"))
	y2milestone("this is a test");

    else if (size(new_list) > 100)
	y2error("Too big list!");

    else if (contains(new_list, "string"))
	y2milestone("this is a new list");

    else
	y2error("Undefined behavior for list %1", new_list);
}