View Compilation Error

0_0_11410423_27752.cpp: In function `int main()':
0_0_11410423_27752.cpp:18: error: `a' undeclared (first use this function)
0_0_11410423_27752.cpp:18: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_11410423_27752.cpp:18: error: expected `;' before "day"