int S(void) { int n; if(lookahead == 'a') { match('a'); n = S(); match('a'); return n; } else if(lookahead == 'b') { int n; match('b')' n = S(); match('b'); return n; } else { n = L(); return n; } } int L(void) { int n; if(lookahead == 'c') { match('c'); n = L(); return n + 1; } else { return 0; } }