/in/foo.cc: In function 'int idea_1(int)':
/in/foo.cc:13:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int idea_2(int, int)':
/in/foo.cc:22:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int idea_3(int, int)':
/in/foo.cc:32:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^