hey every one

i'm new here i have visit this forum many times but today i just register i have a big big problem >__< i try to solve it but i can't

its about the The Predicate Calculus

this is its rule

Every atomic sentence is a sentence

If s is a sentence, then so is its negation, Øs.

If s1 and s2 are sentences, then so is their conjunction, s1 Ù s2.

If s1 and s2 are sentences, then so is their disjunction, s1 Ú s2.

If s1 and s2 are sentences, then so is their implication, s1 Þ s2.

If s1 and s2 are sentences, then so is their equivalence, s1 = s2.

If X is a variable and s a sentence, then " X s is a sentence.

If X is a variable and s a sentence, then $ X s is a sentence.

and the qustion is to transfer this to c++ code

function verify_sentence(expression)

begin

case

expression is an atomic sentence:return SUCCESS

expression is of the form QXs, where Q is either or

, X is a variable,

if verify_sentence(s) returns SUCCESS

then return SUCCES

else return FAIL;

expression is of the form s:

if verify_sentence(s) returns SUCCESS

then return SUCCES

else return FAIL;

expression is of the form s1 op s2, where op is a

binary logical operator:

if verify_sentence(s1) return SUCCESS and

verify_sentence(s2) return SUCCESS

then return SUCCESS

else return FAIL;

otherwise : return FAIL

end

end.

i belive we have to solve it by switch but i don't understand how can we make it , it have to many complex cases