Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

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

func max(x, y int) int {
	if x > y {
		return x
	} else {
		return y
	}
}

func main() {
	sum := make([]int, 5001)
	for {
		n := nextInt()
		if n == 0 {
			break
		}
		for i := 0; i < n; i++ {
			a := nextInt()
			sum[i+1] = sum[i]+a
		}
		ret := sum[1]
		for i := 0; i <= n; i++ {
			for j := i + 1; j <= n; j++ {
				ret = max(ret, sum[j]-sum[i])
			}
		}
		fmt.Println(ret)
	}
}

C++: #include<bits/stdc++.h>
using namespace std;
#define ll long long 
int main(){
    ll n;
    cin >> n;
    while(n!=0){
        vector<ll> vec(n);
        for(ll i=0;i<n;i++){
            cin >> vec.at(i);
        }
        vector<ll> rsw(n+1);
        rsw.at(0) = 0;
        for(int i=1;i<n+1;i++){
            rsw.at(i) = rsw.at(i-1) + vec.at(i-1);
        }
        ll ans = vec.at(0);
        for(int i=0;i<n;i++){
            for(int j=i;j<n;j++){
                if(ans < rsw.at(j+1)-rsw.at(i)){
                    ans = rsw.at(j+1) - rsw.at(i);
                }
            }
        }
        cout << ans << endl;
        cin >> n;

    }
}

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

int main(){
    int n;
    cin>>n;
    while(n!=0){
        vector<int> a(n);
        for(int i=0;i<n;i++) cin>>a[i];
        vector<int> S(n+1);
        for(int i=0;i<=n;i++){
            S[i] = S[i-1] + a[i-1];
        }

        int ans =0;
        int sum =0;

        for(int i=n;i>0;i--){
            for(int j=0;j<n;j++){
                int tmp=S[i] - S[j];
                if(ans<tmp){
                    ans = tmp;
                }
            }
        }
        cout<<ans<<endl;
        cin>>n;
    }
    return 0;
}

C++: #ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#endif
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#ifdef __GXX_EXPERIMENTAL_CXX0X__
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#endif

#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>

#ifdef __GXX_EXPERIMENTAL_CXX0X__
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#endif

using namespace std;

int main()
{
	int N;
	while (cin >> N, N)
	{
		vector<long long int>data;
		data.resize(N + 1);
		data[0] = 0;
		for (size_t i = 1; i <= N; i++)
		{
			cin >> data[i];
			data[i] += data[i - 1];
		}
		long long int ans = INT_MIN;
		for (size_t i = 0; i < N + 1; i++)
		{
			for (size_t j = i+1; j < N + 1; j++)
			{
				ans = max(ans, data[j] - data[i]);
			}
		}
		cout << ans << endl;
	}
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int main()
{
	while (1) {
		int n, i, j, a[5000], maxa = -100001, c;
		cin >> n;
		if (n == 0) {
			break;
		}
		for (i = 0; i < n; i++) {
			cin >> a[i];
		}
		for (i = 0; i < n; i++) {
			c = 0;
			for (j = i; j < n; j++) {
				c+= a[j];
				maxa = max(maxa, c);
			}
		}
		cout << maxa << endl;
	}
	return 0;
}

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

int main()
{

	int n, num;
	vector< int > a;

	while( 1 ) {

		int Max = -100000;

		cin >> n;
		if( n == 0 ) break;

		for( int i = 0; i < n; i++ ) {
		
			cin >> num;
			a.push_back( num );
			
		}

		for( int i = 1; i < n - 1; i++ ) {
		
			a.at( i - 1 ) + a.at( i ) > a.at( i ) ? a.at( i ) = a.at( i - 1 ) + a.at( i ) : a.at( i ) = a.at( i );

			if ( a.at( i ) > Max ) {
				Max = a.at( i );
			}
		
		}

		cout << Max << endl;

		a.clear();
	
	}

	return 0;

}

C++: #line 1 "cumulative_sum.test.cpp"
#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/solutions/problem/0022/review/4031365/toof/C++14"

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vl = vector<ll>;
#define rep(i, n) for(ll i = 0;i < n;i++)
#define all(i) i.begin(), i.end()
template<class T, class U> bool cmax(T& a, U b) { if (a<b) {a = b; return true;} else return false; }
template<class T, class U> bool cmin(T& a, U b) { if (a>b) {a = b; return true;} else return false; }

#line 1 "../cumulative_sum.cpp"
template<class T>
struct CumulativeSum {
  vector<T> v;

  CumulativeSum(size_t n) : v(n+1) {};
  CumulativeSum(vector<T> v_) {
    v.resize(v_.size()+1);
    for (size_t i = 0; i < v_.size(); i++) v[i+1] = v_[i];
  };

  void add(size_t i, T x) {
    v[i+1] += x;
  }

  // O(N)
  void build() {
    for (size_t i = 0; i < v.size()-1; i++)
      v[i+1] += v[i];
  }

  // O(1) sum [l, r]
  T sum(size_t l, size_t r) const {
    return l == 0 ? v[r+1] : v[r+1]-v[l];
  }

  // O(1) sum [0, r]
  T sum(size_t r) const {
    return v[r+1];
  }

  T& operator[](size_t i) {
    return v[i];
  }

  const T& operator[](size_t i) const {
    return v[i];
  }
};
#line 15 "cumulative_sum.test.cpp"

int main() {
  cin.tie(0); ios::sync_with_stdio(false);

  while (true) {
    ll n;
    cin >> n;
    if (n == 0) break;

    vector<ll> v(n);
    rep(i, n) {
      cin >> v[i];
    }

    CumulativeSum<ll> c(v);
    c.build();

    ll ans = -1e10;
    rep(i, n) {
      for (ll j = i; j < n; j++) {
        cmax(ans, c.sum(i, j));
      }
    }
    cout << ans << endl;
  }
}

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

int a[5000];
bool flg[5000];
vector<int> vec;

int sum(int i, int j);

int main()
{
	int n, i, j, k, l, s, max;

	while (cin >> n)
	{
		if (n == 0) break;

		for (i = 0; i < n; i++)
			cin >> a[i];

		max = -2147483647;
		for (i = 0; i < n; i++)
		{
			for (j = i; j < n; j++)
				if ((s = sum(i, j)) > max)
					max = s;
			vec.clear();
			flg[i] = false;
		}
		cout << max << endl;
	}
	return 0;
}

int sum(int a, int b)
{
	int tmp;
	if (!flg[a])
	{
		vec.push_back(::a[a]);
		flg[a] = true;
	}
	if (b-a-1 >= 0)
	{
		vec.push_back(vec[b-a-1]+::a[b]);
	}
		return vec.back();
}

C++: #include <iostream>
using namespace std;
int main (){
long n,dset[5000],temp=0,MINEdset[5000],max=0,h[5000],b=0;
while (1){
cin>>n;
if (n==0)break;
for (int i=0;i<n;i++){
        cin>>dset[i];
}
for (int i=0;i<n;i++){
        for (int j=i;j<n;j++){
                temp=temp+dset[j];
                MINEdset[j]=temp;
        }
        for (int j=i;j<n;j++){
                if (max<MINEdset[j]){
                        max=MINEdset[j];
                }
        }
        h[b]=max;
        max=0;
        b++;
        temp=0;
}
max=-99999;
for (int i=0;i<b;i++){
        if (max<h[i]){
                max=h[i];
        }
}
cout<<max<<endl;
}
return 0;
}