View Compilation Error

0_0_28213057_489.cpp: In function 'int main()':
0_0_28213057_489.cpp:6:5: error: 'f' was not declared in this scope
     f[1] = 2;
     ^
0_0_28213057_489.cpp:11:20: error: 'num' was not declared in this scope
             cin >> num;
                    ^