/in/foo.cc:3:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:6:11: error: cannot convert 'double' to 'const char*' for argument '1' to 'int scanf(const char*, ...)'
  scanf(x,n)
           ^