Main.cc: In function 'int FanXuShu(int)': Main.cc:31:2: warning: no return statement in function returning non-void [-Wreturn-type] } ^ Main.cc: At global scope: Main.cc:32:2: error: expected unqualified-id before 'return' return b; ^ Main.cc:33:1: error: expected declaration before '}' token } ^