View Compilation Error

0_0_17991514_25347.cpp:2:1: error: '_int64' does not name a type
 _int64 f(int n)
 ^
0_0_17991514_25347.cpp: In function 'int main()':
0_0_17991514_25347.cpp:15:2: error: '_int64' was not declared in this scope
  _int64 a[10000];
  ^
0_0_17991514_25347.cpp:18:7: error: 'a' was not declared in this scope
       a[n]=f(n)%2009;
       ^
0_0_17991514_25347.cpp:18:15: error: 'f' was not declared in this scope
       a[n]=f(n)%2009;
               ^
0_0_17991514_25347.cpp:20:26: error: 'a' was not declared in this scope
            printf("%d\n",a[n%4018]);
                          ^