Go: package main

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

const (
	initialBufSize = 1e4
	maxBufSize     = 1e6 + 7
)

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

func init() {
	sc.Split(bufio.ScanWords)
	sc.Buffer(buf, maxBufSize)
}

func main() {
	for {
		n := nextInt()
		if n == 0 {
			break
		}
		an := make([]int, n)
		min := 1000000
		for i := 0; i < n; i++ {
			an[i] = nextInt()
		}
		sort.Ints(an)
		for i := 1; i < n; i++ {
			sub := an[i] - an[i-1]
			if min > sub {
				min = sub
			}
		}
		fmt.Println(min)
	}
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

C++: #pragma region Macros

#include<bits/stdc++.h>
using namespace std;

#define rep(i,n) for(long long i=0;i<n;i++)
#define REP(i,s,n) for(long long i=(s);i<=(n);i++)
#define repr(i,n) for(long long i=n-1;i>=0;i--)
#define REPR(i,s,n) for(long long i=(s);i>=(n);i--)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define Eunique(v) v.erase(unique(all(v)),v.end())
#define Eback(s) s.erase(s.end()-1,s.end())
#define minvec(v) *min_element(all(v))
#define maxvec(v) *max_element(all(v))
#define sumvec(v) accumulate(all(v),0LL)
#define pb push_back
#define pf push_front
#define m_p make_pair
#define DOUBLE fixed << setprecision(15)
#define OK cerr<<"OK\n"
#define OK1 cerr<<"OK1\n"
#define OK2 cerr<<"OK2\n"
#define sz(s) (long long)s.size()
#define INF ((1LL<<62)-(1LL<<31))
#define zero(x,n) setw(x) << setfill('0') << n
#define endl '\n'

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef vector<double> vd;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef vector<vd> vvd;
typedef vector<vc> vvc;
typedef vector<vb> vvb;
typedef pair<ll,ll> P;
typedef vector<P> vP;
typedef queue<ll> qll;
typedef priority_queue<ll> pqll;

template<class A, class B>
ostream& operator<<(ostream& ost, const pair<A, B>&p) {
	ost << "{" << p.first << ", " << p.second << "} ";
	return ost;
}

template<class T>
ostream& operator<<(ostream& ost, const vector<T>&v) {
	ost << "{";
	for (int i = 0; i<(int)v.size(); i++) {
		if (i)ost << " ";
		ost << v[i];
	}
	ost << "} \n";
	return ost;
}

template<class A, class B>
ostream& operator<<(ostream& ost, const map<A, B>&v) {
	ost << "{";
	for (auto p:v) {
		ost << "{" << p.first << ", " << p.second << "} ";
	}
	ost << "} ";
	return ost;
}

void out(){cout << "\n";}
template<class T,class... Args>
void out(const T &x,const Args &... args){
	cout << x << " ";
	out(args...);
}

template<typename T>
istream& operator >> (istream& is, vector<T>& vec){
	for(T& e: vec) is >> e;
	return is;
}

template<typename T>
string join(vector<T>& vec, string sep=" "){
	stringstream ss;
	for(int i=0;i<(int)vec.size();i++){
		ss << vec[i] << (i+1==(int)vec.size()?"\n":sep);
	}
	return ss.str();
}

template<class T>
inline bool chmax(T& a, T b){if(a<b){a=b;return true;} return false;}

template<class T>
inline bool chmin(T& a, T b){if(a>b){a=b;return true;} return false;}

#define INT(...) int __VA_ARGS__;IN(__VA_ARGS__)
#define LL(...) long long __VA_ARGS__;IN(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;IN(__VA_ARGS__)
#define DBR(...) double __VA_ARGS__;IN(__VA_ARGS__)
#define STR(...) string __VA_ARGS__;IN(__VA_ARGS__)
#define LD(...) long double __VA_ARGS__;IN(__VA_ARGS__)

void scan(int& a){ cin >> a; }
void scan(long long& a){ cin >> a; }
void scan(char& a){ cin >> a; }
void scan(double& a){ cin >> a; }
void scan(string& a){ cin >> a; }
void scan(long double& a){ cin >> a; }

void IN(){}
template<class Head,class... Tail> void IN(Head& head,Tail&... tail){ scan(head); IN(tail...); }

void YES(bool b) {cout << ((b)?"YES\n":"NO\n");}
void Yes(bool b) {cout << ((b)?"Yes\n":"No\n");}
void yes(bool b) {cout << ((b)?"yes\n":"no\n");}
void Yay(bool b) {cout << ((b)?"Yay!\n":":(\n");}

const long double pi = acos(-1.0);
const ll mod=1000000007;
//const ll mod=998244353;

ll powmod(ll a,ll b){ll c=1; while(b>0){ if(b&1){ c=a*c%mod; } a=a*a%mod; b>>=1; } return c;}
ll invmod(ll a){ return powmod(a,mod-2); }
ll nCrmod(ll n,ll r){ll x=1,y=1; for(ll i=0;i<r;i++) {x=x*(n-i)%mod; y=y*(i+1)%mod; } return x*powmod(y,mod-2)%mod;}
ll gcd(ll a,ll b){ while(b){ ll c=b; b=a%b; a=c; } return a; }
ll lcm(ll a,ll b){ if(!a || !b) return 0; return a*b/gcd(a,b); }
vll divisor(ll x){ vll v; for(int i=1;i*i<=x;i++)if(x%i==0){ v.pb(i);if(i*i!=x)v.pb(x/i); } sort(all(v)); return v; };
map<ll,ll> prime_factor(ll n){ map<ll,ll> m; for(ll i=2;i*i<=n;i++){ while(n%i==0){ m[i]++; n /= i; } }if(n!=1) m[n]=1; return m; }

#pragma endregion

int main()
{
	ll n;
	while(cin >> n,n){
		vll a(n);
		cin >> a;
		sort(all(a));
		ll ans=INF;
		rep(i,n-1) chmin(ans,a[i+1]-a[i]);
		cout << ans << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

#define int long long
typedef vector<int>vint;
typedef pair<int,int>pint;
typedef vector<pint>vpint;
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define all(v) (v).begin(),(v).end()
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
#define pb push_back
#define fi first
#define se second
template<typename A,typename B>inline void chmin(A &a,B b){if(a>b)a=b;}
template<typename A,typename B>inline void chmax(A &a,B b){if(a<b)a=b;}

signed main(){
    int n;
    while(cin>>n,n){
        vint a(n);
        rep(i,n)cin>>a[i];
        sort(all(a));
        int mi=LLONG_MAX;
        rep(i,n-1)chmin(mi,a[i+1]-a[i]);
        cout<<mi<<endl;
    }
    return 0;
}

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

int main(void){
  int n;
  int a[1000]={};
  int min=1000000;
  cin>>n;
  while(n!=0){
    min=1000000;
    for(int i=0;i<n;i++){
      cin>>a[i];
    }
    for(int i=0;i<n;i++){
      for(int j=0;j<n;j++){
	if(i!=j){
	  int sa;
	  if(0>(a[i]-a[j])){
	    sa=a[j]-a[i];
	  }else{
	    sa=a[i]-a[j];
	  }
	  //  cout<<sa<<" "<<min<<endl;
	  if(sa<min)min=sa;
	  //  cout<<sa<<" "<<min<<endl;
	}
      }
    }
    cout<<min<<endl;
    cin>>n;
  }
}

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

int main(){
    while(true){
        int n;
        cin >> n;
        if(n==0) break;
        int a[n];
        for(int i=0; i<n; i++){
            cin >> a[i];
        }
        int min1=abs(a[1]-a[0]);
        for(int i=0; i<n; i++){
            for(int j=0; j<n; j++){
                if(j != i && min1 > abs(a[j]-a[i])) min1 = abs(a[j] - a[i]);
            }
        }
        cout << min1 << endl;
    }

    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
int main() {
	int n;
	while (cin >> n) {
		if (n == 0)return 0;
		vector<long long>l;
		for (int i = 0; i < n; i++) {
			long long a; cin >> a;
			l.push_back(a);
		}
		sort(l.begin(), l.end());
		long long num = l[1] - l[0];
		for (int i = 1; i < n - 1; i++) {
			num = min(num, l[i] - l[i - 1]);
		}
		cout << num << endl;
	}
}

C++: #include <stdio.h>
#include <iostream>
#include <math.h>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;
#define ll long long
#define pb push_back

int main()
{
    int n;
    vector<int> x;
    while (1)
    {
        cin >> n;
        if (n == 0)
        {
            break;
        }
        int min = 1000000;
        vector<int> a(n);
        for(int i=0; i<n;i++){
            cin >> a[i];
        }
        sort(a.begin(),a.end());
        for(int i=0; i<n-1;i++){
            int diff = abs(a[i] - a[i+1]);
            if(diff < min){
                min = diff;
            }
        }
        x.push_back(min);
    }
    for (int i = 0; i < x.size(); i++)
    {
        cout << x[i] << endl;
    }
}