class LonelyGuy { friend class LonelyGuy; };
Standard input is empty
prog.cpp:3:18: warning: class ‘LonelyGuy’ is implicitly friends with itself [enabled by default] /usr/lib/gcc/i486-linux-gnu/4.7/../../../i386-linux-gnu/crt1.o: In function `_start': (.text+0x18): undefined reference to `main' collect2: error: ld returned 1 exit status
Standard output is empty