Go: package main

import (
        "fmt"
)

func main() {
        for {
                var n int
                _, err := fmt.Scanf("%d", &n)
                if err != nil || n == 0 {
                        break
                }

                var sum [5001]int

                for i := 1; i <= n; i++ {
                        fmt.Scanf("%d", &(sum[i]))
                        if i > 1 {
                                sum[i] += sum[i-1]
                        }
                }

                max_sum := sum[1]
                for i := 1; i <= n; i++ {
                        for j := 0; j < i; j++ {
                                if max_sum < sum[i] - sum[j] {
                                        max_sum = sum[i] - sum[j]
                                }
                        }
                }
                fmt.Printf("%d\n", max_sum)
        }
}

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

//define-----------------------------------------------------------------------------------------------------------------------
#define rep(i, n) for(int i = 0; i < (int)n; i++)
#define FOR(i, s, n) for(int i = s; i < (int)n; i++)
#define per(i, n) for(int i = n; i >= 0; i--)
#define ROF(i, s, n) for(int i = s; i >= (int)n; i--)
#define FORIT(i, A) for (auto i : A)
#define PRINT(x) cout << (x) << "\n"
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define EACH(i, n) for (__typeof((n).begin()) i = (n).begin(); i != (n).end(); ++i)
#define SZ(a) int((a).size())
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define CLR(a) memset((a), 0 ,sizeof(a))
#define dump(x) cout << #x << " = " << (x) << "\n";
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << "\n";
#define sq(n) (n) * (n)

//typedef----------------------------------------------------------------------------------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef priority_queue<int> maxpq;
typedef priority_queue< int, vector<int>, greater<int> > minpq;
//const------------------------------------------------------------------------------------------------------------------------
static const double EPS = 1e-10;
static const double PI = acos( -1.0 );
static const int mod = 1000000007;
static const int INF = 1 << 25;

//global-----------------------------------------------------------------------------------------------------------------------
LL a, b, n, ans = 0;
vector<LL> ar;
vector<LL> sum_ar;
//#define DEBUG
//function--------------------------------------------------------------------------------------------------------------------

int main() {
	while ( scanf( "%lld", &n ) && n ) {
		sum_ar.PB( 0 );
		ans = 0;
		rep( i, n ) {
			scanf( "%lld", &a );
			ar.PB( a );
			sum_ar.PB( sum_ar[ i ] + a );
		}
		rep( i, n ) {
			FOR( j, i + 1, n + 1 ) {
#ifdef DEBUG
				debug(i)
				debug(j)
#endif
				ans = max( ans, sum_ar[ j ] - sum_ar[ i ] );
			}
		}
		printf( "%lld\n", ans );
		sum_ar = vector<LL>();
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define pq priority_queue
using namespace std; typedef pair<int, int> P; typedef pair<int, P> P2;
typedef pair<int, P2> P3; typedef long long ll; typedef long double ld;
constexpr long long gcd(long long a, long long b){return b ? gcd(b, a % b) : a;}
constexpr long long lcm(long long a, long long b){return a / gcd(a, b) * b;}
constexpr int INF = 1e9, MOD = INF + 7, around[] = {0, 1, 1, -1, -1, 0, -1, 1, 0, 0};
constexpr int mod_pow(long long x, long long n, const int mod){long long ret=1;while(n){if(n&1)(ret*=x)%=mod;(x*=x)%=mod;n>>=1;}return ret;}
template<int n> struct Prime{bool arr[n+1];constexpr bool operator[](int k){return arr[k];}constexpr Prime():arr(){for(int i=2;i<n;i++){arr[i]=true;for(int j=2;j*j<=i;j++){if(!(i%j))arr[i]=false;}}}};
template<int n> struct Factorial{long long arr[n+1],ary[n+1];constexpr Factorial():arr(),ary(){arr[0]=1;ary[0]=1;for(int i=0;i<n;i++){arr[i+1]=arr[i]*(i+1)%MOD;ary[i+1]=mod_pow(arr[i+1],MOD-2,MOD);}}};
constexpr Factorial<1010> fact; constexpr Prime<10> prime;
constexpr long long comb(int a, int b){if(a < b) return 0LL;if(!a or !b) return 1LL; long long pos = fact.arr[a], pot = fact.ary[a - b], por = fact.ary[b]; return pos * pot % MOD * por % MOD;}
template<int n> struct Bernoulli{long long arr[n+1];constexpr Bernoulli():arr(){arr[0]=1;for(int i=1;i<=n;i++){long long sum=0;for(int j=0;j<i;j++){(sum+=comb(i+1,j)*arr[j]%MOD)%=MOD;}arr[i]=(MOD-mod_pow(i+1,MOD-2,MOD))%MOD*sum%MOD;}}};
constexpr int vx[] = {1, 0, -1, 0}, vy[] = {0, 1, 0, -1};
constexpr int sqrtN = 512, logN = 32;
constexpr ld PI = abs(acos(-1));
constexpr ll LINF=1e18;

template<typename T>
struct CumulativeSum{
	vector<T> data;
	
	CumulativeSum(int n) : data(n + 1, 0) {}

	void add(int k, T x){data[k + 1] += x;} //0 - indexed
	void build(){
		for(int i = 0; i < data.size() - 1; i++){
			data[i + 1] += data[i];
		}
	}
	
	T get(int a, int b){ //1 - indexed
		a = max(0, a - 1);
		b = min((int)data.size() - 1, b);
		
		return data[b] - data[a];
	}
	
	T get(int a){ //1 - indexed
		return data[a];
	}
};

int main(){
	int n; 
	while(cin >> n, n){
		CumulativeSum<int> sum(n);
		for(int i = 0; i < n; i++){
			int a; cin >> a;
			sum.add(i, a);
		}
		sum.build();
		
		int ma = 0;
		for(int i = 1; i <= n; i++){
			for(int j = i + 1; j <= n; j++){
				ma = max(ma, sum.get(i, j));
			}
		}
		
		cout << ma << endl;
	}
	return 0;
}

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;
}

C++: #include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
#define all(x) (x).begin(),(x).end()
#define rep(i,n) for(int (i)=0;i<(n);i++)
#define REP(i,m,n) for(int (i)=(m);(i)<(n);(i)++)
#define INF LLONG_MAX - 100
#define MOD 1000000007
#define fcout cout << fixed << setprecision(15)
#define int long long
#define yorn(f) puts((f)?"Yes":"No")
#define YORN(f) puts((f)?"YES":"NO")
#define lower_bound lowb
#define upper_bound upb
typedef long long ll;
typedef pair<int, int> P;
typedef priority_queue<int> pque;
int gcd(int a,int b){return b?gcd(b,a%b):a;};
int lcm(int a,int b){return a*b/gcd(a,b);};
int mod(int a,int b){return (a+b-1)/b;};
template<typename A, size_t N, typename T>
void Fill(A(&array)[N],const T &val){std::fill((T*)array,(T*)(array+N),val);}
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;};

int dp[5050];

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

    int n;
    while(true) {
        cin >> n;
        if(!n) break;
        int a[n];
        rep(i, n) cin >> a[i];

        int ret = INT_MIN, nres = 0;
        rep(i, n) {
            if(nres < 0) nres = a[i];
            else nres += a[i];
            chmax(ret, nres);
        }

        cout << ret << endl;
    }
    return 0;
}