View Compilation Error

0_0_7568309_7401.cpp: In function `int main()':
0_0_7568309_7401.cpp:17: error: `Xi' undeclared (first use this function)
0_0_7568309_7401.cpp:17: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_7568309_7401.cpp:17: error: expected primary-expression before '!=' token