What kind of a structure can the cddr procedure be applied
to? What must its operand look like?
The operand must be a pair in which the second component is also a pair.
Which of the elements of such a structure does cddr
return?
It returns the second component of the second component of its operand:
What happens if the structure has the wrong shape?> (define example-1 (cons #f (cons #f #t))) > (cddr example-1) #t > (define example-2 (cons (cons 1 2) (cons 3 4))) > (cddr example-2) 4
It is an error, so under most implementations the program crashes:
> (cddr (cons (cons 1 2) 3)) ERROR: cddr: Wrong type in arg1 3
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