Area Separation http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=2009

aoj2009.cpp

#include <bits/stdc++.h>
using namespace std;
#define int long long   // <-----!!!!!!!!!!!!!!!!!!!

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n)-1;i>=0;i--)
#define rrep2(i,a,b) for (int i=(a)-1;i>=b;i--)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define printV(_v) for(auto _x:_v){cout<<_x<<" ";}cout<<endl
#define printVS(vs) for(auto x : vs){cout << x << endl;}
#define printVV(_vv) for(auto _v:_vv){for(auto _x:_v){cout<<_x<<" ";}cout<<endl;}
#define printP(p) cout << p.first << " " << p.second << endl
#define printVP(vp) for(auto p : vp) printP(p);
#define readV(_v) rep(j, _v.size()) cin >> _v[j];
#define readVV(_vv) rep(i, _vv.size()) readV(_vv[i]);
#define output(_x) cout << _x << endl;

typedef long long ll;
typedef pair<int, int> Pii;
typedef tuple<int, int, int> TUPLE;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<Pii> vp;
const int inf = 1e9;
const int mod = 1e9 + 7;

typedef complex<double> P;
typedef vector<P> G;
#define here(g, i) g[i]
#define next(g, i) g[(i + 1) % g.size()]
#define prev(g, i) g[(i - 1 + g.size()) % g.size()]
const double EPS = 1e-10;
const double INF = 1e12;
const double PI = acos(-1);

struct L {
    P a, b, v;
    L(){}
    L(P _a, P _b) : a(_a), b(_b), v(b - a) {}
    L(double _ax, double _ay, double _bx, double _by) : L(P(_ax, _ay), P(_bx, _by)) {}
};


double cross(P a, P b) {
    return imag(conj(a) * b);
}

double dot(P a, P b) {
    return real(conj(a) * b);
}

int ccw(P p0, P p1, P p2) {
    if (cross(p1 - p0, p2 - p0) > 0) return +1; // counter-clockwise
    if (cross(p1 - p0, p2 - p0) < 0) return -1; // clockwise
    if (dot(p1 - p0, p2 - p0) < 0) return +2;   // online_back
    if (dot(p0 - p1, p2 - p1) < 0) return -2;   // online_front
    return 0;                                   // on_segment
}

bool intersectSS(L l1, L l2) {
    return (ccw(l1.a, l1.b, l2.a) * ccw(l1.a, l1.b, l2.b) < 0 &&
            ccw(l2.a, l2.b, l1.a) * ccw(l2.a, l2.b, l1.b) < 0);
}

P crosspointSS(L l1, L l2) {
    double d1 = abs(cross(l2.v, l1.a - l2.a));
    double d2 = abs(cross(l2.v, l1.b - l2.a));
    double t = d1 / (d1 + d2);
    return l1.a + t * l1.v;
}

L readL() {
    double xa, ya, xb, yb;
    cin >> xa >> ya >> xb >> yb;
    return L(xa, ya, xb, yb);
}

int Count(vector<P> p) {
    int n = p.size();
    int ret = 0;
    rep(i, n) {
        bool flag = true;
        rep(j, i) {
            if (p[i] == p[j]) {
                flag = false;
                break;
            }
        }
        ret += flag;
    }
    return ret;
}

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

    int n;
    while (cin >> n, n) {
        int ans = 1;
        vector<L> l(n);
        rep(i, n) {
            l[i] = readL();
            vector<P> p;
            rep(j, i) {
                if (intersectSS(l[i], l[j])) {
                    p.emplace_back(crosspointSS(l[i], l[j]));
                }
            }
            ans += Count(p) + 1;
        }
        cout << ans << endl;
    }
}