/in/foo.cc: In function 'bool is_prime(int)':
/in/foo.cc:8:2: error: 'retun' was not declared in this scope
  retun true;
  ^~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:27:24: warning: too many arguments for format [-Wformat-extra-args]
  printf("%d\n",n,result);
                        ^
/in/foo.cc: In function 'bool is_prime(int)':
/in/foo.cc:9:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^