View Compilation Error

0_0_31679652_28551.cpp: In function 'int main()':
0_0_31679652_28551.cpp:5:2: error: '_int64' was not declared in this scope
  _int64 a[21],num1,num2;
  ^
0_0_31679652_28551.cpp:6:2: error: 'a' was not declared in this scope
  a[1]=0;a[2]=1;
  ^
0_0_31679652_28551.cpp:11:3: error: 'num1' was not declared in this scope
   num1=1;num2=1;
   ^
0_0_31679652_28551.cpp:11:10: error: 'num2' was not declared in this scope
   num1=1;num2=1;
          ^