Language: C++

#define ALL(obj) (obj).begin(),(obj).end()
#define INF 1000000000000000
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
using namespace std;
typedef long long ll;
typedef double db;
typedef string str;
typedef pair<ll,ll> p;
constexpr int MOD = 1000000007;

void print(const std::vector<int>& v)
{
  std::for_each(v.begin(), v.end(), [](int x) {
    std::cout << x << " ";
  });
  std::cout << std::endl;
}

int main ()
{
  int N;
  if (N>= 1000) N -= 999;
  cout<<"ABC"<<swet(3)<<setfill('0') << N<<endl;
  return 0;
}

Compiler output:
a.cc:8:9: error: 'string' does not name a type
    8 | typedef string str;
      |         ^~~~~~
a.cc:9:9: error: 'pair' does not name a type
    9 | typedef pair<ll,ll> p;
      |         ^~~~
a.cc:12:23: error: 'vector' in namespace 'std' does not name a template type
   12 | void print(const std::vector<int>& v)
      |                       ^~~~~~
a.cc:1:1: note: 'std::vector' is defined in header '<vector>'; this is probably fixable by adding '#include <vector>'
  +++ |+#include <vector>
    1 | #define ALL(obj) (obj).begin(),(obj).end()
a.cc:12:29: error: expected ',' or '...' before '<' token
   12 | void print(const std::vector<int>& v)
      |                             ^
a.cc: In function 'void print(int)':
a.cc:14:8: error: 'for_each' is not a member of 'std'
   14 |   std::for_each(v.begin(), v.end(), [](int x) {
      |        ^~~~~~~~
a.cc:14:17: error: 'v' was not declared in this scope
   14 |   std::for_each(v.begin(), v.end(), [](int x) {
      |                 ^
a.cc: In lambda function:
a.cc:15:10: error: 'cout' is not a member of 'std'
   15 |     std::cout << x << " ";
      |          ^~~~
a.cc:1:1: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
  +++ |+#include <iostream>
    1 | #define ALL(obj) (obj).begin(),(obj).end()
a.cc: In function 'void print(int)':
a.cc:17:8: error: 'cout' is not a member of 'std'
   17 |   std::cout << std::endl;
      |        ^~~~
a.cc:17:8: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:17:21: error: 'endl' is not a member of 'std'
   17 |   std::cout << std::endl;
      |                     ^~~~
a.cc:1:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
  +++ |+#include <ostream>
    1 | #define ALL(obj) (obj).begin(),(obj).end()
a.cc: In function 'int main()':
a.cc:24:3: error: 'cout' was not declared in this scope
   24 |   cout<<"ABC"<<swet(3)<<setfill('0') << N<<endl;
      |   ^~~~
a.cc:24:3: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:24:16: error: 'swet' was not declared in this scope
   24 |   cout<<"ABC"<<swet(3)<<setfill('0') << N<<endl;
      |                ^~~~
a.cc:24:25: error: 'setfill' was not declared in this scope
   24 |   cout<<"ABC"<<swet(3)<<setfill('0') << N<<endl;
      |                         ^~~~~~~
a.cc:1:1: note: 'std::setfill' is defined in header '<iomanip>'; this is probably fixable by adding '#include <iomanip>'
  +++ |+#include <iomanip>
    1 | #define ALL(obj) (obj).begin(),(obj).end()
a.cc:24:44: error: 'endl' was not declared in this scope
   24 |   cout<<"ABC"<<swet(3)<<setfill('0') << N<<endl;
      |                                            ^~~~
a.cc:24:44: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'