Go: package main

import "fmt"

func main() {
	var n, coins, change int
	for {
		fmt.Scan(&n)
		if n == 0 {
			return
		}
		coins = 0
		change = 1000 - n
		for change > 0 {
			coins++
			switch {
			case change >= 500:
				change -= 500
			case change < 500 && change >= 100:
				change -= 100
			case change < 100 && change >= 50:
				change -= 50
			case change < 50 && change >= 10:
				change -= 10
			case change < 10 && change >= 5:
				change -= 5
			default:
				change--
			}
		}
		fmt.Println(coins)
	}
}

C++: // https://onlinejudge.u-aizu.ac.jp/challenges/sources/JOI/Prelim/0521?year=2008

#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;

    while (cin >> n, n) {
        n = 1000 - n;

        int a = n / 500;
        n %= 500;

        int b = n / 100;
        n %= 100;

        int c = n / 50;
        n %= 50;

        int d = n / 10;
        n %= 10;

        int e = n / 5;
        int f = n % 5;

        int ans = a + b + c + d + e + f;
        cout << ans << endl;
    }
    return 0;
}

/*
 * 
 */

C++: #define _CRT_SECURE_NO_WARNINGS
#include "bits/stdc++.h"
#include <random>

using namespace std;

//呪文
#define DUMPOUT cerr
#define dump(...) DUMPOUT<<"  ";DUMPOUT<<#__VA_ARGS__<<" :["<<__LINE__<<":"<<__FUNCTION__<<"]"<<endl;DUMPOUT<<"    ";dump_func(__VA_ARGS__)

typedef unsigned uint; typedef long long ll; typedef unsigned long long ull; typedef pair<int, int> pii; typedef pair<ll, ll> pll; typedef pair<double, double> pdd; typedef pair<string, string> pss;
template <typename _KTy, typename _Ty> ostream& operator << (ostream& ostr, const pair<_KTy, _Ty>& m) { ostr << "{" << m.first << ", " << m.second << "}"; return ostr; }
template <typename _KTy, typename _Ty> ostream& operator << (ostream& ostr, const map<_KTy, _Ty>& m) { if (m.empty()) { ostr << "{ }"; return ostr; } ostr << "{" << *m.begin(); for (auto itr = ++m.begin(); itr != m.end(); itr++) { ostr << ", " << *itr; } ostr << "}"; return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const vector<_Ty>& v) { if (v.empty()) { ostr << "{ }"; return ostr; } ostr << "{" << v.front(); for (auto itr = ++v.begin(); itr != v.end(); itr++) { ostr << ", " << *itr; }	ostr << "}"; return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const set<_Ty>& s) { if (s.empty()) { ostr << "{ }"; return ostr; } ostr << "{" << *(s.begin()); for (auto itr = ++s.begin(); itr != s.end(); itr++) { ostr << ", " << *itr; }	ostr << "}"; return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const stack<_Ty>& s) { if (s.empty()) { ostr << "{ }"; return ostr; } stack<_Ty> t(s); ostr << "{" << t.top(); t.pop(); while (!t.empty()) { ostr << ", " << t.top(); t.pop(); } ostr << "}";	return ostr; }
template <typename _Ty> ostream& operator << (ostream& ostr, const list<_Ty>& l) { if (l.empty()) { ostr << "{ }"; return ostr; } ostr << "{" << l.front(); for (auto itr = ++l.begin(); itr != l.end(); ++itr) { ostr << ", " << *itr; } ostr << "}"; return ostr; }
template <typename _KTy, typename _Ty> istream& operator >> (istream& istr, pair<_KTy, _Ty>& m) { istr >> m.first >> m.second; return istr; }
template <typename _Ty> istream& operator >> (istream& istr, vector<_Ty>& v) { for (size_t i = 0; i < v.size(); i++) istr >> v[i]; return istr; }
namespace aux { // print tuple
	template<typename Ty, unsigned N, unsigned L> struct tp { static void print(ostream& os, const Ty& v) { os << get<N>(v) << ", "; tp<Ty, N + 1, L>::print(os, v); } };
	template<typename Ty, unsigned N> struct tp<Ty, N, N> { static void print(ostream& os, const Ty& value) { os << get<N>(value); } };
}
template<typename... Tys> ostream& operator<<(ostream& os, const tuple<Tys...>& t) { os << "{"; aux::tp<tuple<Tys...>, 0, sizeof...(Tys)-1>::print(os, t); os << "}"; return os; }

template<typename A, size_t N, typename T> inline void Fill(A(&array)[N], const T &val) { std::fill((T*)array, (T*)(array + N), val); }

void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail> void dump_func(Head&& head, Tail&&... tail) { DUMPOUT << head; if (sizeof...(Tail) == 0) { DUMPOUT << " "; } else { DUMPOUT << ", "; } dump_func(std::move(tail)...); }

#define PI 3.14159265358979323846
#define EPS 1e-11
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define all(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define fake false



int main()
{
	//clock_t start, end;
	//start = clock();

	cin.tie(0);
	ios::sync_with_stdio(false);

	int c[] = { 500, 100, 50, 10, 5, 1 };

	while (true) {
		int N;
		cin >> N;
		if (N == 0) break;

		int x = 1000 - N;
		int ans = 0;
		for (int i = 0; i < 6; i++) {
			ans += x / c[i];
			x %= c[i];
		}
		cout << ans << endl;
	}

	//end = clock();
	//printf("%d msec.\n", end - start);

	return 0;
}

C++: #include <iostream>
using namespace std;

int main()
{
int value, coins = 0;
while(true){
cin >> value;
if(value == 0) break;
value = 1000-value;
coins += value/500; value%=500;
coins += value/100; value%=100;
coins += value/50; value%=50;
coins += value/10; value%=10;
coins += value/5; value%=5;
coins += value;
cout << coins << endl;
coins = 0;
}
return 0;
}

C++: #include<iostream>
using namespace std;

int p[6] = {500, 100, 50, 10, 5, 1};

int main(){
	int n, ans = 0;
	cin >> n;
	n = 1000 - n;

	for(int i=0; i < 6; i++){
		ans += n / p[i];
		n -= n / p[i] * p[i];
	}
	cout << ans << endl;
}

C++: //============================================================================
// Name        : 0521.cpp
// Author      : 
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================

#include <iostream>
using namespace std;

int main() {
	int x;
	int c[6]={
		500,100,50,10,5,1
	};
	while(1){
		int ans=0;
	cin>>x;
	x=1000-x;
	if(x==0){
		break;
	}
	for(int i=0;i<6;i++){
		ans=x/c[i]+ans;
		x=x%c[i];

	}
	cout <<ans<<endl;
	}
	return 0;
}

C++: #include <stdio.h>
#include <stdlib.h>

int main(){
	int okane;
	int oturi;
	int count = 0;
	int a[] = { 1, 5, 10, 50, 100, 500 };

	scanf("%d", &okane);
	oturi = 1000 - okane;

	for (int i = 5; i >= 0; i--){
		if (oturi >= a[i]){
			div_t d;

			d = div(oturi, a[i]);
			oturi = oturi - a[i] * d.quot;
			count = count + d.quot;
		}
	}
	printf("%d\n",count);

	return 0;

	div(20, 3);

}

C++: #include<iostream>
#include<algorithm>
using namespace std;
#define INF ( 1 << 30 )
int main(){
  int n, dp[1000], tmp[] = {500,100,50,10,5,1};
  fill_n(dp,1000,INF);
  dp[0] = 0;
  for(int i = 0 ; i < 1000 ; i++ ){
    for(int j = 0 ; j < 6 ; j++ ){
      dp[i] = min( dp[i-tmp[j]] + 1, dp[i]);
    }
  }
  while(cin >> n , n ) cout << dp[n] << endl;
}

C++: #include<stdio.h>
int main(void){
	int oturi;
	int mon,i,ans=0;
	int a[5]={500,100,50,10,5};
	while(1){
		ans=0;
		scanf("%d",&mon);
		if(mon==0)break;
		oturi=1000-mon;
		for(i=0;i<5;i++){
			ans+=oturi/a[i];
			oturi%=a[i];
		}
		ans+=oturi;
		printf("%d\n",ans);
	}
}

C++: #include <iostream>
using namespace std;
int main(){
  int n;
  int c[] = {500,100,50,10,5,1};

  while( cin >> n ,n ){
    n = 1000-n;
    int ans = 0;
    for( int i=0;i<6;i++ ){
      if( n >= c[i] ){
	ans += n / c[i];
	n = n% c[i];
      }
    }
    cout << ans << endl;
  }
}