Compilare: user.cpp:1:35: warning: invalid suffix on literal; C++11 requires a space between literal and identifier [-Wliteral-suffix] #define k(x,i,r)b;std::x##fstream("adunare."i)r ^ user.cpp:3:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main(){int a,k(i,"in",>>a>>k(o,"out",<<a+b;})) ^