View Compilation Error

0_0_32417101_13326.cpp: In function 'int main()':
0_0_32417101_13326.cpp:4:2: error: '__int64' was not declared in this scope
  __int64 a[51];
  ^
0_0_32417101_13326.cpp:5:3: error: 'a' was not declared in this scope
   a[1]=3;
   ^
0_0_32417101_13326.cpp:12:22: error: 'scanf' was not declared in this scope
   while(scanf("%d",&n)!=EOF)
                      ^
0_0_32417101_13326.cpp:12:25: error: 'EOF' was not declared in this scope
   while(scanf("%d",&n)!=EOF)
                         ^
0_0_32417101_13326.cpp:14:24: error: 'printf' was not declared in this scope
   printf("%I64d\n",a[n]);
                        ^