View Compilation Error

0_0_34906940_22299.cpp: In function 'int main()':
0_0_34906940_22299.cpp:12:18: error: invalid types 'char [200020][char*]' for array subscript
             a[a+i]=a[i];    
                  ^
0_0_34906940_22299.cpp:13:17: error: invalid operands of types 'char [200020]' and 'char [200020]' to binary 'operator+'
             a[a+a]='\0';
                 ^