Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func main() {
	x := make([]int, 100)
	y := make([]int, 100)
	r := make([]int, 100)
	for scanner.Scan() {
		a, _ := strconv.Atoi(scanner.Text())
		if a == 0 {
			break
		}
		for i := 0; i < a; i++ {
			scanner.Scan()
			input := strings.Split(scanner.Text(), " ")
			tmpx, _ := strconv.Atoi(input[0])
			tmpy, _ := strconv.Atoi(input[1])
			tmpr, _ := strconv.Atoi(input[2])
			x[i], y[i], r[i] = tmpx, tmpy, tmpr
		}
		scanner.Scan()
		b, _ := strconv.Atoi(scanner.Text())
		for i := 0; i < b; i++ {
			scanner.Scan()
			input := strings.Split(scanner.Text(), " ")
			c, _ := strconv.Atoi(input[0])
			d, _ := strconv.Atoi(input[1])
			e, _ := strconv.Atoi(input[2])
			f, _ := strconv.Atoi(input[3])
			ok := false
			for j := 0; j < a; j++ {
				if (c-x[j])*(c-x[j])+(d-y[j])*(d-y[j]) >= r[j]*r[j] || (e-x[j])*(e-x[j])+(f-y[j])*(f-y[j]) >= r[j]*r[j] {
					if (e-c)*(x[j]-c)+(f-d)*(y[j]-d) < 0 {
						if (x[j]-c)*(x[j]-c)+(y[j]-d)*(y[j]-d) <= r[j]*r[j] {
							ok = true
						}
					} else {
						if (e-c)*(x[j]-c)+(f-d)*(y[j]-d)>(e-c)*(e-c)+(f-d)*(f-d) {
							if (x[j]-e)*(x[j]-e)+(y[j]-f)*(y[j]-f)<=r[j]*r[j] {
								ok = true
							}
						} else {
							if (x[j]-c)*(x[j]-c)+(y[j]-d)*(y[j]-d)-((e-c)*(x[j]-c)+(f-d)*(y[j]-d))*((e-c)*(x[j]-c)+(f-d)*(y[j]-d))/((e-c)*(e-c)+(f-d)*(f-d))<=r[j]*r[j] {
								ok = true
							}
						}
					}

				}
			}
			if ok {
				fmt.Println("Safe")
			} else {
				fmt.Println("Danger")
			}
		}
	}
}

C++: /**************** Geometrical Library ****************/

#include<cmath>
#include<vector>
#include<algorithm>

#define	EPS	1e-9

enum {CCW=1,CW=-1,ON=0};

#define	mp	make_pair
#define	pb	push_back

using namespace std;

class Point{
public:
	double x,y;
	Point(){}
	Point(double xx,double yy):x(xx),y(yy){}
};

class Line:public vector<Point>{
public:
	Line(const Point &a,const Point &b){
		pb(a),pb(b);
	}
};

class Segment:public Line{
public:
	Segment(const Point &a,const Point &b):Line(a,b){}
};

class Polygon:public vector<Point>{};

class Circle{
public:
	Point c;
	double r;
	Circle(){}
	Circle(const Point &cc,double rr):c(cc),r(rr){}
};

Point &operator +=(Point &a,const Point &b){
	a.x+=b.x,a.y+=b.y;
	return a;
}

Point &operator -=(Point &a,const Point &b){
	a.x-=b.x,a.y-=b.y;
	return a;
}

Point &operator *=(Point &a,double c){
	a.x*=c,a.y*=c;
	return a;
}

Point &operator /=(Point &a,double c){
	a.x/=c,a.y/=c;
	return a;
}

Point operator +(const Point &a,const Point &b){
	Point c=a;
	return c+=b;
}

Point operator -(const Point &a,const Point &b){
	Point c=a;
	return c-=b;
}

Point operator *(double c,const Point &a){
	Point b=a;
	return b*=c;
}

Point operator /(const Point &a,double c){
	Point b=a;
	return b/=c;
}

bool operator <(const Point &a,const Point &b){
	return (a.x==b.x)?(a.y<b.y):(a.x<b.x);
}

bool operator >(const Point &a,const Point &b){
	return b<a;
}

double dot(const Point &a,const Point &b){
	return a.x*b.x+a.y*b.y;
}

double cross(const Point &a,const Point &b){
	return a.x*b.y-a.y*b.x;
}

double norm2(const Point &a){
	return dot(a,a);
}

int ccw(const Point &a,Point b,Point c){
	b-=a,c-=a;
	double rotdir=cross(b,c);
	if(rotdir>EPS)		return CCW;
	if(rotdir<-EPS)		return CW;
	return ON;
}

inline void calc_abc(const Line &l,double &a,double &b,double &c){	// l : ax+by+c=0
	a=l[0].y-l[1].y;
	b=l[1].x-l[0].x;
	c=l[0].x*l[1].y-l[1].x*l[0].y;
}

Point perp_foot(const Point &p,const Line &l){
	double a,b,c;
	calc_abc(l,a,b,c);
	return p-(a*p.x+b*p.y+c)/(a*a+b*b)*Point(a,b);
}

int intersect(const Circle &c,const Line &l,Point *p=NULL,Point *q=NULL){
	Point m=perp_foot(c.c,l);
	double d2=norm2(c.c-m);
	if(c.r*c.r+EPS<d2)	return 0;
	else if(abs(c.r*c.r-d2)<EPS){
		if(p&&q)	*p=*q=m;
		return 1;
	}
	else{
		if(p&&q){
			double n0=norm2(l[0]-m),n1=norm2(l[1]-m);
			Point v;
			if(n0<n1)	v=l[1]-m,n0=n1;
			else		v=l[0]-m;
			v*=sqrt((c.r*c.r-d2)/n0);
			*p=m+v,*q=m-v;
		}
		return 2;
	}
}

int intersect(const Circle &c,const Segment &s,Point *p=NULL,Point *q=NULL){
	Point pp,qq;
	int n=intersect(c,Line(s[0],s[1]),&pp,&qq);
	if(n==0)	return 0;
	else if(n==1){
		if(dot(pp-s[0],pp-s[1])<EPS){
			if(p&&q)	*p=*q=pp;
			return 1;
		}
		return 0;
	}
	else{
		bool bp=(dot(pp-s[0],pp-s[1])<EPS);
		bool bq=(dot(qq-s[0],qq-s[1])<EPS);
		if(bp&&bq){
			if(p&&q)	*p=pp,*q=qq;
			return 2;
		}
		if(bp||bq){
			if(p&&q)	*p=(bp?pp:qq);
			return 1;
		}
		return 0;
	}
}

/**************** Library END ****************/

#include<cstdio>

int main(){
	for(int n;scanf("%d",&n),n;){
		Circle wall[100];
		for(int i=0;i<n;i++){
			int x,y,r;	scanf("%d%d%d",&x,&y,&r);
			wall[i]=Circle(Point(x,y),r);
		}

		int m;	scanf("%d",&m);
		while(m--){
			Point taro,oni;	scanf("%lf%lf%lf%lf",&taro.x,&taro.y,&oni.x,&oni.y);
			Segment view(taro,oni);
			bool ok=false;
			for(int i=0;i<n;i++){
				if(intersect(wall[i],view)>0){
					ok=true;
					break;
				}
			}
			puts(ok?"Safe":"Danger");
		}
	}

	return 0;
}

C++: #include<cstdio>
#include<vector>

#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;

template<class T>
struct point{
	T x,y;
	point operator-(const point &a)const{ return (point){x-a.x,y-a.y}; }
};

template<class T>
struct segment:vector< point<T> >{
	segment(const point<T> &a,const point<T> &b){ push_back(a), push_back(b); }
};

template<class T>
struct circle{
	point<T> c;
	T r;
};

template<class T>
T dot(const point<T> &a,const point<T> &b){ return a.x*b.x+a.y*b.y; }

template<class T>
T cross(const point<T> &a,const point<T> &b){ return a.x*b.y-a.y*b.x; }

template<class T>
T dist2(const point<T> &a,const point<T> &b){
	return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);
}

template<class T>
T dist2(const segment<T> &S,const point<T> &p){
	if(dot(S[1]-S[0],p-S[0])<=0) return dist2(p,S[0]);
	if(dot(S[0]-S[1],p-S[1])<=0) return dist2(p,S[1]);
	return cross(S[1]-S[0],p-S[0])*cross(S[1]-S[0],p-S[0])/dist2(S[0],S[1]);
}

template<class T>
bool intersect(const circle<T> &C,const segment<T> &S){
	return dist2(S,C.c)<=C.r*C.r;
}

template<class T>
bool cover(const circle<T> &C,const point<T> &p){
	return dist2(C.c,p)<=C.r*C.r;
}

template<class T>
bool cover(const circle<T> &C,const segment<T> &S){
	return cover(C,S[0]) && cover(C,S[1]);
}

int main(){
	for(int n;scanf("%d",&n),n;){
		circle<int> C[100];
		rep(i,n) scanf("%d%d%d",&C[i].c.x,&C[i].c.y,&C[i].r);

		int m; scanf("%d",&m);
		while(m--){
			point<int> p,q;
			scanf("%d%d%d%d",&p.x,&p.y,&q.x,&q.y);
			segment<int> S(p,q);
			bool ok=false;
			rep(i,n) if(intersect(C[i],S) && !cover(C[i],S)) ok=true;
			puts(ok?"Safe":"Danger");
		}
	}

	return 0;
}