View Compilation Error

0_0_25617734_28713.cpp: In function 'int main()':
0_0_25617734_28713.cpp:15:28: error: invalid types 'int[int]' for array subscript
             scanf("%d",&a[i]);
                            ^
0_0_25617734_28713.cpp:16:41: error: invalid types 'int[int]' for array subscript
         double ans = floor(sqrt(fabs(a[1]-a[n]))+0.1);
                                         ^
0_0_25617734_28713.cpp:16:46: error: invalid types 'int[int]' for array subscript
         double ans = floor(sqrt(fabs(a[1]-a[n]))+0.1);
                                              ^