Go: package main

import (
	"fmt"
	"os"
	"strconv"
	"strings"
	"bufio"
)

var (
	sc = bufio.NewScanner(os.Stdin)
	buf = make([]byte, 1000)
)

func scanText() string{
	sc.Scan()
	return sc.Text()
}

func scanTextArray(n int) []string {
	out := make([]string, n)
	for i, v := range(strings.Split(scanText(), "")) {
		out[i] = v
	}
	return out
}

func scanInt() int {
	out, e := strconv.Atoi(scanText())
	if e != nil {
        panic(e)
    }
	return out
}

func scanIntArray(n int) []int {
	out := make([]int, n)
	for i, v := range(strings.Split(scanText(), " ")) {
		num, e := strconv.Atoi(v)
		if e != nil {
			panic(e)
		}
		out[i] = num
	}
	return out
}
//  template end

var (
	coins = [6]int{500, 100, 50, 10, 5, 1}
)

func f(data int) {
	ans := 0
	change := 1000 - data
	for _, v := range coins {
		for ;v <= change; {
			change -= v
			ans++
		}
	}
	fmt.Println(ans)
}

func main() {
	sc.Buffer(buf, 10000)
	for{
		data := scanInt()
		if data == 0 {
			break
		}
		f(data)
	}
}

C++: #include <iostream>
using namespace std;
int main(void){
    // Your code here!
  
  while(true){
   int t;
 cin>>t;
   if(t==0){
   break;
   }
    
  
 int s=1000-t;
 int w=s/500;
 int e=(s%500)/100;
  int r=((s%500)%100)/50;
  int y=(((s%500)%100)%50)/10;
  int u=((((s%500)%100)%50)%10)/5;
  int o=(((((s%500)%100)%50)%10)%5);
  cout<< w+e+r+y+u+o <<endl;
}
}

C++: #include <iostream>
#include <string>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    int a[5];
    for (int i = 0; i < 5; i++) cin >> a[i];
    
    for (int i = 0; i < 5; i++) {
        int count = 0;
        int n = 1000-a[i];
        while (n % 500 == 0) {
            n -= 500;
            count++;
        }
        while (n % 100 == 0) {
            n -= 100;
            count++;
        }
        while (n % 50 == 0) {
            n -= 50;
            count++;
        }
        while (n % 10 == 0) {
            n -= 10;
            count++;
        }
        while (n % 5== 0) {
            n -= 5;
            count++;
        }
        count += n;
        
        cout << count << endl;
    }
    
    return 0;
}

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

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

int main(){
  int c,t;
  int ans;
  
  while(true){
    
    scanf(" %d",&c);
    if(c==0)break;
    
    t = 1000 - c;
    
    ans = 0;
    for(int i=0;i<6;i++){
      while(t>=coin[i]){
        t-=coin[i];
        ans++;
      }
    }
    
    printf("%d\n",ans);
  }
  
  return 0;
}

C++: #include <cstdio>
#include <utility>
#include <vector>
using namespace std;

#define gcu getchar_unlocked
#define ii inline int in
#define is inline bool scan
ii(int c) {
	int n = 0;
	bool minus = false; if (c == '-') minus = true, c = gcu();
	do {n = 10 * n + (c - '0'), c = gcu();} while (c >= '0');
	//return n; }
	return minus ? -n : n; }
ii() {return in(gcu());}
is(int &n) {int c=gcu();return c==EOF?false:(n=in(c),true);}
is(char &c){c=gcu();gcu();return c!=EOF;}
//is(string &s) {int c;for(;;){c=gcu();if(c=='\n'||c==' ')return true;s+=c;}}
#undef ii
#define pcu putchar_unlocked
template <typename T>
void out(T n) {
	static char buf[20];
	char *p = buf;
	if(n < 0) pcu('-'), n *= -1;
	if (!n) *p++ = '0';
	else while (n) *p++ = n % 10 + '0', n /= 10;
	while (p != buf) pcu(*--p); }
void out(const char *s){while(*s)pcu(*s++);}
void out(char c){pcu(c);}
//void out(string &s){for (char c: s) pcu(c);}
template <typename head, typename... tail>
void out(head&& h, tail&&... t){out(h);out(move(t)...);}
template <typename T>
//void out(vector<T> &v){for(T &x:v)out(' '),out(x);out('\n');}
void out(vector<T> &v){for(T &x:v)out(&x == &v[0]?"":" "),out(x);out('\n');}
#undef svo

int main() {
	int price;
	while ((price = in())) {
		int change = 1000 - price, coins = 0;
		for (int c : {500, 100, 50, 10, 5, 1}) {
			coins += change / c;
			change %= c;
			if (!change)
				break;
		}
		out(coins, '\n');
	}
}

C++: //include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef unsigned long long ULL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

int main() {
  int n, money, change;
  int coin[6] = {500, 100, 50, 10, 5, 1};

  while(1) {
    cin >> money;
    if(!money) break;

    change = 1000-money;

    int cnt = 0;
    REP(i, 6) {
      while(change/coin[i] > 0) {	
	cnt++;
	change -= coin[i];
      }
    }
    cout << cnt << endl;
  }
}

C++: #include <stdio.h>
#include <vector>
#include <algorithm>
#include <stack>

using namespace std;


int main(){

	int coin[6] ={ 500,100,50,10,5,1 },sum,price;

	while(true){
		scanf("%d",&price);
		if(price == 0)break;

		sum = 0;

		price = 1000 - price;

		for(int i = 0; i <= 5; i++){
			while(price >= coin[i]){
				price -= coin[i];
				sum++;
			}
		}

		printf("%d\n",sum);
	}

    return 0;
}

C++: #include <stdio.h>

#define COINNUM 6
#define PAY 1000

int main(void){
	const int coins[COINNUM] = {500, 100, 50, 10, 5, 1};
	int price;
	int back;
	int num = 0;
	
	scanf("%d", &price);
	back = PAY - price;
	
	for (int i=0; i<COINNUM; i++){
		while (back >= coins[i]){
			num++;
			back -= coins[i];
//			printf("%d, ", coins[i]);
		}
	}
	printf("%d", num);
	
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <queue>
#include <string.h>

using namespace std;

int k[10];
int coins[6] = {500,100,50,10,5,1};
int cnt[5];
int amt;

int main(){
  	cin >> k[0];
    for(int i = 1; k[i-1]; i++){
        cin >> k[i];
      	k[i-1] = 1000 -k[i-1];
      	amt++;
    }

    for(int i = 0; k[i]; i++){
        for(int j = 0; j < 6; j++){
            while(k[i] - coins[j] >= 0){
                k[i] -= coins[j];
                cnt[i]++;
            }
        }
    } 

    for(int i = 0; i < amt; i++){
        cout << cnt[i] <<  endl;
    }
}

C++: #include<iostream>
using namespace std;
int main(void)
{
    int mone,A,A1;
    cin>>mone;
    A=1000-mone;
    A1=A%500;
    A=A/500+A1/100+A1%100/50+A1%100%50/10+A1%100%50%10/5+A1%100%50%10%5;
    cout<<A<<"\n";
}