View Compilation Error

0_0_31693885_16119.cpp: In function 'int main()':
0_0_31693885_16119.cpp:14:12: error: 'i' was not declared in this scope
          ; i<=maxn; i++) a[i]=;
            ^
0_0_31693885_16119.cpp:27:24: error: 'ans' was not declared in this scope
          printf("%d\n",ans);
                        ^