View Compilation Error

0_0_5179915_29309.cpp: In function `int main()':
0_0_5179915_29309.cpp:22: error: `A' undeclared (first use this function)
0_0_5179915_29309.cpp:22: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5179915_29309.cpp:22: error: expected `;' before "if"
0_0_5179915_29309.cpp:24: error: expected primary-expression before "else"
0_0_5179915_29309.cpp:24: error: expected `;' before "else"