View Compilation Error

0_0_1794336_7300.cpp: In function `int main()':
0_0_1794336_7300.cpp:8: error: `X' undeclared (first use this function)
0_0_1794336_7300.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1794336_7300.cpp: At global scope:
0_0_1794336_7300.cpp:18: error: expected declaration before '}' token