Go: package main

import (
	"fmt"
	"math"
)

func main() {
	var n int
	fmt.Scan(&n)
	for i := 0; i < n; i++ {
		var xa, ya, ra, xb, yb, rb float64
		fmt.Scan(&xa, &ya, &ra, &xb, &yb, &rb)
		// println(xa, ya, ra, xb, yb, rb)
		dis := math.Sqrt((xa-xb)*(xa-xb) + (ya-yb)*(ya-yb))
		if dis + ra < rb {
			fmt.Println(-2)
		} else if dis + rb < ra {
			fmt.Println(2)
		} else if dis > rb + ra {
			fmt.Println(0)
		} else {
			fmt.Println(1)
		}
	}
}

C++: // AOJ 0023
#include<iostream>
#define REP(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;

const double EPS = 1e-7;

double sq(double x) {
  return x * x;
}

double abs(double x) {
  return (x > 0 ? x : -x);
}

bool eq(double x, double y) {
  return abs(x - y) < EPS;
}

double dist(int xa, int ya, int xb, int yb) {
  return sq(xa - xb) + sq(ya - yb);
}

int main() {
  int n;
  cin >> n;
  REP(i, n) {
    double xa, ya, ra, xb, yb, rb;
    cin >> xa >> ya >> ra >> xb >> yb >> rb;

    double d = dist(xa, ya, xb, yb);
    
    if (d < sq(ra)) {
      cout << 2 << endl;
    } else if (d < sq(rb)) {
      cout << -2 << endl;
    } else if (eq(d, ra) or eq(d, rb)) {
      cout << 1 << endl;
    } else if (d < ra + rb) {
      cout << 1 << endl;
    } else {
      cout << 0 << endl;
    }
  }
}

C++: #include<iostream>
#include<cmath>


int main(){
  int n;
  double xa,ya,ra,xb,yb,rb,d;
  std::cin >> n;

  for(int i=0;i<n;i++){
    std::cin >> xa >> ya >> ra
             >> xb >> yb >> rb;
    d = std::sqrt((xa-xb)*(xa-xb)+(ya-yb)*(ya-yb));
    /*if(ra+rb < d){
      std::cout << (int)0 << std::endl;
      break;
    }
    if(ra+d < rb){
      std::cout << (int)-2 << std::endl;
      break;
    }
    if(rb+d < ra){
      std::cout << (int)2 << std::endl;
    }else{
      std::cout << (int)1 << std::endl;
    }*/
    cout << (d<=ra+rb?d+rb>=ra?d+ra>=rb?1:-2:2:0) << endl;
  }
}

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

/* 平面幾何の基本要素 */
 
#define EPS (1e-10)
#define equals(a,b) (fabs((a) - (b)) < EPS )
 
class Point { // 点を表すクラス
public:
  double x,y;
  
  Point(double x=0,double y=0): x(x),y(y) {}
  
  Point operator + (Point p) { return Point(x + p.x, y + p.y); }
  Point operator - (Point p) { return Point(x - p.x, y - p.y); }
  Point operator * (double a) { return Point(a * x, a * y); }
  Point operator / (double a) { return Point(x / a, y / a); }
  
  double abs() { return sqrt(norm()); }
  double norm() { return x * x + y * y; }
  
  bool operator < (const Point &p) const {
    return x != p.x ? x < p.x : y < p.y;
  }
  
  bool operator == (const Point &p) const {
    return fabs(x - p.x) < EPS && fabs(y - p.y) < EPS;
  }
};

typedef Point Vector; // ベクトルを表す構造体

struct Segment { // 線分を表す構造体
  Point p1,p2;
};

typedef Segment Line; // 直線を表す構造体

class Circle { // 円を表すクラス
public:
  Point c;
  double r;
  Circle(Point c = Point(), double r = 0.0): c(c),r(r) {}
};
typedef vector < Point > Polygon; // 多角形

double dot(Vector a, Vector b) {
  return a.x * b.x + a.y * b.y;
}
 
double cross(Vector a, Vector b) {
  return a.x * b.y - a.y * b.x;
}

static const int COUNTER_CLOCKWISE = 1;
static const int CLOCKWISE = -1;
static const int ONLINE_BACK = 2;
static const int ONLINE_FRONT = -2;
static const int ON_SEGMENT = 0;
 
int ccw(Point p0, Point p1, Point p2) {
  Vector a = p1 - p0;
  Vector b = p2 - p0;
 
  if( cross(a,b) > EPS ) return COUNTER_CLOCKWISE;
  if( cross(a,b) < -EPS ) return CLOCKWISE;
  if( dot(a,b) < -EPS ) return ONLINE_BACK;
  if( a.norm() < b.norm() ) return ONLINE_FRONT;
 
  return ON_SEGMENT;
}

bool intersect(Point p1,Point p2,Point p3,Point p4){
  return ( ccw(p1,p2,p3) * ccw(p1,p2,p4) <= 0 && 
	   ccw(p3,p4,p1) * ccw(p3,p4,p2) <= 0);
}

bool intersect(Segment s1,Segment s2){
  return intersect(s1.p1,s2.p1,s1.p2,s2.p2);
}

int contains(Polygon g,Point p){
  int n = g.size();
  bool x = false;
  for(int i=0;i<n;i++){
    Point a = g[i] - p, b = g[(i+1)%n] - p;
    if(abs(cross(a,b)) < EPS && dot(a,b) < EPS) return 1;
    if(a.y > b.y) swap(a,b);
    if(a.y < EPS && EPS < b.y && cross(a,b) > EPS) x = !x;
  }
  return (x ? 2 : 0);
}

/*
double distance( Point p1,Point p2){
  return sqrt( (p1.y - p2.y) * (p1.y - p2.y) + (p1.x - p2.x) * (p1.x - p2.x));
}
*/

double distance( double y1, double x1, double y2, double x2){
  return sqrt( (y1 - y2) * (y1 - y2) + (x1 - x2) * (x1 - x2));
}

int main(){
  Point p1,p2,p3,p4;
  double ra,rb;
  int n;
  cin >> n;
  while(n--){
    cin >> p1.x >> p1.y >> ra >> p2.x >> p2.y >> rb;
    double d = distance(p1.y,p1.x,p2.y,p2.x);
    int ret = 1;
    if(d > ra + rb) ret = 0;
    if(d + ra < rb) ret = -2;
    if(d + rb < ra) ret = 2;
    cout << ret << endl;
  }
}

C++: #include <iostream>
#include <cmath>

using namespace std;

int main()
{
    double xa, ya, ra, xb, yb, rb;
    double d;
    int num;

    cin >> num;
    for (int i = 0; i < num; i++) {
        cin >> xa >> ya >> ra >> xb >> yb >> rb;
        
        ra *= ra;
        rb *= rb;
        d = (xa - xb) * (xa - xb) + (ya - yb) * (ya - yb);

        if (d > ra + rb) 
            cout << 0 << endl;
        else {
            if ((abs(ra - rb) < d) && (d < abs(ra + rb)))
                cout << 1 << endl;
            else if (d < abs(ra - rb))
                cout << 2 << endl;
            else
                cout << -2 << endl;
        }
    }

    return 0;
}

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

int main()
{
	int n;
	double xa, ya, ra, xb, yb, rb;
	double eps = -1e-8;
	
	cin >> n;
	while(n--){
		cin >> xa >> ya >> ra >> xb >> yb >> rb;
		//B in A
		if( hypot(xa - xb, ya - yb) + rb + eps < ra )
			cout << 2 << endl;
		//A in B
		else if( hypot(xa - xb, ya - yb) + ra + eps < rb )
			cout << -2 << endl;
		//A intersect B
		else if( hypot(xa - xb, ya - yb) + eps < ra + rb )
			cout << 1 << endl;
		else
			cout << 0 << endl;
	}
	return 0;
}

C++: #include <iostream>

using namespace std;


int main()
{
  int i;
  cin>>i;
  for(;i--;)
    {

      double xa,ya,ra,xb,yb,rb;     
      int ans;
      cin>>xa>>ya>>ra>>xb>>yb>>rb;
      double d = (xa-xb)*(xa-xb)+(ya-yb)*(ya-yb);
      if(d  > (ra+rb)*(ra+rb))
	ans = 0;
      else if (d <= (ra-rb)*(ra-rb) && ra>rb)
	ans = 2;
      else if (d  <= (rb-ra)*(rb-ra) && rb>ra)
	ans =-2;
      else
	ans =-1;
      cout<<ans<<endl;

    }

}

C++: #include <iostream>
#include <array>

inline double squ_minus(double a, double b){
	double x = a - b;
	return x * x;
}

inline double squ_plus(double a, double b){
	double x = a + b;
	return x * x;
}

int main(){
	int n; // the number of datasets
	std::cin >> n;
	
	for(int i = 0; i < n; ++i){
		std::array<double, 6> cir; // 0:xa, 1:ya, 2:ra, 3:xb, 4:yb, 5:rb
		std::cin >> cir[0] >> cir[1] >> cir[2] >> cir[3] >> cir[4] >> cir[5];

		double dis = squ_minus(cir[0], cir[3]) + squ_minus(cir[1], cir[4]);
		
		if(dis > squ_plus(cir[2], cir[5])){
			std::cout << "0" << std::endl;
		}else if(dis < squ_minus(cir[2], cir[5])){
			std::cout << (cir[2] >= cir[5] ? "2" : "-2") << std::endl;
		}else{
			std::cout << "1" << std::endl;
		}
	}
	return 0;
}

C++: #include <iostream>
#include <cmath>
#define double long double
using namespace std;

int main()
{
	int n;
	double xa, ya, ra, xb, yb, rb;
	
	cin >> n;
	while(n--){
		cin >> xa >> ya >> ra >> xb >> yb >> rb;
		//B in A
		if( hypot(xa - xb, ya - yb) + rb < ra )
			cout << 2 << endl;
		//A in B
		else if( hypot(xa - xb, ya - yb) + ra < rb )
			cout << -2 << endl;
		//A intersect B
		else if( hypot(xa - xb, ya - yb) < ra + rb )
			cout << 1 << endl;
		else
			cout << 0 << endl;
	}
	return 0;
}