View Compilation Error

0_0_1768896_17780.cpp: In function `int main()':
0_0_1768896_17780.cpp:10: error: `A' undeclared (first use this function)
0_0_1768896_17780.cpp:10: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1768896_17780.cpp:10: error: `B' undeclared (first use this function)