View Compilation Error

0_0_36696937_9818.cpp: In function 'int main()':
0_0_36696937_9818.cpp:11:3: error: 'a' was not declared in this scope
   a[2]=29;
   ^
0_0_36696937_9818.cpp:13:12: error: 'a' was not declared in this scope
    ans=ans+a[i];
            ^