View Compilation Error

0_0_33754010_8453.cpp: In function 'int main()':
0_0_33754010_8453.cpp:22:4: error: 'a' was not declared in this scope
   }a
    ^
0_0_33754010_8453.cpp:23:17: error: 'i' was not declared in this scope
   for(int i=n-1;i>=1;i--){
                 ^