View Compilation Error

0_0_3100159_8004.cpp: In function `int main()':
0_0_3100159_8004.cpp:6: error: `EFO' undeclared (first use this function)
0_0_3100159_8004.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_3100159_8004.cpp:9: error: expected `;' before "return"