View Compilation Error

0_0_31418179_21417.cpp: In function 'int main()':
0_0_31418179_21417.cpp:11:27: error: 'a' was not declared in this scope
             scanf("%lld",&a[i]);
                           ^
0_0_31418179_21417.cpp:13:29: error: 'a' was not declared in this scope
             printf("%lld\n",a[0]);
                             ^