View Compilation Error

0_0_15734874_13151.cpp: In function 'int main()':
0_0_15734874_13151.cpp:5:2: error: '_int64' was not declared in this scope
  _int64 a[55]={1,2};
  ^
0_0_15734874_13151.cpp:6:19: error: 'a' was not declared in this scope
  for(i=2;i<55;i++)a[i]=a[i-1]+a[i-2];
                   ^
0_0_15734874_13151.cpp:9:20: error: 'a' was not declared in this scope
   printf("%I64d\n",a[n-1]);
                    ^