View Compilation Error

0_0_15735041_12626.cpp: In function 'int main()':
0_0_15735041_12626.cpp:5:2: error: '_int64' was not declared in this scope
  _int64 a[55]={1,1,2};
  ^
0_0_15735041_12626.cpp:6:19: error: 'a' was not declared in this scope
  for(i=3;i<51;i++)a[i]=a[i-1]+a[i-2];
                   ^
0_0_15735041_12626.cpp:9:20: error: 'a' was not declared in this scope
   printf("%I64d\n",a[n]);
                    ^