View Compilation Error

0_0_16600920_21330.cpp:4:2: error: 'cin' does not name a type
  cin>>a;
  ^
0_0_16600920_21330.cpp:5:2: error: expected unqualified-id before 'while'
  while(a--)
  ^
0_0_16600920_21330.cpp:7:2: error: expected unqualified-id before 'return'
  return 0;
  ^
0_0_16600920_21330.cpp:8:1: error: expected declaration before '}' token
 }
 ^