foo.cpp: In function 'int main()':
foo.cpp:19:9: error: expected ';' before 'if'
         if (n & 1)
         ^
foo.cpp:21:9: error: 'else' without a previous 'if'
         else
         ^
foo.cpp:26:41: warning: unknown conversion type character 'l' in format [-Wformat=]
     ans = printf("%lld\n", ans / (2 * n));
                                         ^
foo.cpp:26:41: warning: too many arguments for format [-Wformat-extra-args]