View Compilation Error

0_0_27357333_4568.cpp: In function 'int main()':
0_0_27357333_4568.cpp:9:39: error: 'memset' was not declared in this scope
         memset(array1,0,sizeof(array1));
                                       ^
0_0_27357333_4568.cpp:14:13: error: 'cin' was not declared in this scope
             cin>>array1[i];
             ^
0_0_27357333_4568.cpp:42:9: error: 'cout' was not declared in this scope
         cout<<sum<<endl;
         ^
0_0_27357333_4568.cpp:42:20: error: 'endl' was not declared in this scope
         cout<<sum<<endl;
                    ^