View Compilation Error

0_0_21141484_14802.cpp: In function 'int main()':
0_0_21141484_14802.cpp:12:18: error: 'n' was not declared in this scope
     scanf("%d", &n);
                  ^
0_0_21141484_14802.cpp:19:20: error: 'op' was not declared in this scope
       scanf("%d", &op);
                    ^