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++: #include<deque>
#include<queue>
#include<vector>
#include<algorithm>
#include<iostream>
#include<set>
#include<cmath>
#include<tuple>
#include<string>
#include<chrono>
#include<functional>
#include<iterator>
#include<random>
#include<unordered_set>
#include<array>
#include<map>
#include<iomanip>
#include<assert.h>
#include<bitset>
#include<stack>
#include<memory>
using namespace std;
using namespace std::chrono;
typedef long long int llint;
typedef double lldo;
#define mp make_pair
#define mt make_tuple
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define fir first
#define sec second
#define res resize
#define ins insert
#define era erase
/*cout<<fixed<<setprecision(20);cin.tie(0);ios::sync_with_stdio(false);*/
const llint mod=998244353;
const llint big=2.19e17+1;
const long double pai=3.141592653589793238462643383279502884197;
const long double eps=1e-15;
template <class T,class U>bool mineq(T& a,U b){if(a>b){a=b;return true;}return false;}
template <class T,class U>bool maxeq(T& a,U b){if(a<b){a=b;return true;}return false;}
llint gcd(llint a,llint b){if(a%b==0){return b;}else return gcd(b,a%b);}
llint lcm(llint a,llint b){if(a==0){return b;}return a/gcd(a,b)*b;}
template<class T> void SO(T& ve){sort(ve.begin(),ve.end());}
template<class T> void REV(T& ve){reverse(ve.begin(),ve.end());}
template<class T>llint LBI(vector<T>&ar,T in){return lower_bound(ar.begin(),ar.end(),in)-ar.begin();}
template<class T>llint UBI(vector<T>&ar,T in){return upper_bound(ar.begin(),ar.end(),in)-ar.begin();}
//  17:50-
bool solve(void){
	int n,i;cin>>n;
	if(n==0){return false;}
	vector<int>a(n);
	for(i=0;i<n;i++){cin>>a[i];}
	SO(a);
	int ans=9999999;
	for(i=0;i<n-1;i++){mineq(ans,a[i+1]-a[i]);}
	cout<<ans<<endl;
	return true;
}
int main(void){
	while(solve()){}
	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

template<typename T> istream& operator>>(istream &s, vector<T> &v) {
  for (T &t : v) s >> t;
  return s;
}

template<typename T> ostream& operator<<(ostream &s, const vector<T> &v) {
  for (const T &t : v) s << t << endl;
  return s;
}

template<typename T> T min(vector<T>& v) {return *min_element(v.begin(), v.end());}

template<typename T> T max(vector<T>& v) {return *max_element(v.begin(), v.end());}

template<typename T> int min_element(vector<T>& v) {return min_element(v.begin(), v.end()) - v.begin();}

template<typename T> int max_element(vector<T>& v) {return max_element(v.begin(), v.end()) - v.begin();}

template<typename T> void sort(vector<T>& v) {sort(v.begin(), v.end());}

template<typename T, typename Function> void sort(vector<T>& v, Function func) {sort(v.begin(), v.end(), func);}

template<typename T> void rsort(vector<T>& v) {sort(v.rbegin(), v.rend());}

template<typename T> void reverse(vector<T>& v) {reverse(v.begin(), v.end());}

template<typename T> void unique(vector<T>& v) {v.erase(unique(v.begin(), v.end()), v.end());}

template<typename T> void nth_element(vector<T>& v, int n) {nth_element(v.begin(), v.begin() + n, v.end());}

template<typename T> bool next_permutation(vector<T>& v) {return next_permutation(v.begin(), v.end());}

template<typename T> int find(vector<T>& v, T t) {return find(v.begin(), v.end(), t) - v.begin();}

template<typename T> int in(vector<T> v, T t) {return find(v, t) != int(v.size());}

template<typename T> int lower_bound(vector<T>& v, T t) {return lower_bound(v.begin(), v.end(), t) - v.begin();}

template<typename T> int upper_bound(vector<T>& v, T t) {return upper_bound(v.begin(), v.end(), t) - v.begin();}

template<typename T> T accumulate(const vector<T>& v, function<T(T, T)> func = plus<T>()) {return accumulate(v.begin(), v.end(), T(), func);}

template<typename T> void adjacent_difference(vector<T>& v) {adjacent_difference(v.begin(), v.end(), v.begin());}

template<typename T> void adjacent_difference(vector<T>& v, vector<T>& u) {adjacent_difference(v.begin(), v.end(), u.begin());}

template<typename T> void partial_sum(vector<T>& v, vector<T>& u) {partial_sum(v.begin(), v.end(), u.begin());}

template<typename T> T inner_product(vector<T>& v, vector<T>& u) {return inner_product(v.begin(), v.end(), u.begin(), T(0));}

template<typename T> int count(const vector<T>& v, T t) {return count(v.begin(), v.end(), t);}

template<typename T, typename Function> int count_if(const vector<T>& v, Function func) {return count_if(v.begin(), v.end(), func);}

template<typename T, typename Function> void remove_if(vector<T>& v, Function func) {v.erase(remove_if(v.begin(), v.end(), func), v.end());}

template<typename T, typename Function> bool all_of(vector<T> v, Function func) {return all_of(v.begin(), v.end(), func);}

template<typename T, typename Function> bool any_of(vector<T> v, Function func) {return any_of(v.begin(), v.end(), func);}

template<typename T, typename Function> bool none_of(vector<T> v, Function func) {return none_of(v.begin(), v.end(), func);}

template<typename T> vector<T> subvector(vector<T>& v, int a, int b) {return vector<T>(v.begin() + a, v.begin() + b);}

template<typename T> int kinds(const vector<T>& v) {return set<T>(v.begin(), v.end()).size();}

template<typename T> void iota(vector<T>& v, T t = 0) {iota(v.begin(), v.end(), t);}

template<typename T> bool is_sorted(const vector<T>& v) {return is_sorted(v.begin(), v.end());}

int main() {
  while (true) {
    int n;
    cin >> n;
    if (n == 0) break;
    vector<int> a(n);
    cin >> a;
    sort(a);
    adjacent_difference(a);
    cout << *min_element(a.begin() + 1, a.end()) << endl;
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define all(c) begin(c), end(c)
#define dump(x) cerr << __LINE__ << ":\t" #x " = " << (x) << endl

int main(){
    int n;
    while(cin >> n && n){
        int a[1001];
        rep(i, n) cin >> a[i];
        int ans = 1e9;
        rep(i, n) rep(j, i) ans = min(ans, abs(a[i] - a[j]));
        cout << ans << endl;
    }
}

C++: #include <bits/stdc++.h>

using namespace std;

int main() 
{
    int n;
    while (cin >> n, n) {
        vector<int> s(n);
        for (int i = 0; i < n; i++) {
            cin >> s[i];
        }

        int mi = 999999999;
        for (int i = 0; i < n; i++) {
            for (int j = i+1; j < n; j++) {
                if (mi > abs(s[i] - s[j])) {
                    mi = abs(s[i] - s[j]);
                }
            }
        }
        cout << mi << endl;
    }
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define all(a)  (a).begin(),(a).end()
#define pb emplace_back
#define INF (1e9+1)
//#define INF (1LL<<59)


int main(){
    int n;
    while(cin>>n&&n){
        int ans = INF;
        vector<int> a(n);
        rep(i,n)cin>>a[i];
        rep(i,a.size()){
            rep(j,a.size()){
                if(i==j)continue;
                ans = min(ans,abs(a[i]-a[j]));
            }
        }
        cout<<ans<<endl;
    }
}