Mã chấm: 269137

Main.cc: In function ‘int main()’:
Main.cc:8:5: error: ‘cout’ was not declared in this scope
     cout << numbers::pi
     ^~~~
Main.cc:8:5: note: suggested alternative: ‘cosl’
     cout << numbers::pi
     ^~~~
     cosl
Main.cc:8:13: error: ‘numbers’ has not been declared
     cout << numbers::pi
             ^~~~~~~