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)
		distance := math.Sqrt((xb-xa)*(xb-xa) + (yb-ya)*(yb-ya))
		if rb+distance < ra {
			fmt.Println(2)
		} else if ra+distance < rb {
			fmt.Println(-2)
		} else if rb+ra >= distance {
			fmt.Println(1)
		} else {
			fmt.Println(0)
		}
	}
}

C++: #include<iostream>
#include<cmath>
int main()
{
	int n;
	std::cin >> n;
	for (int i = 0; i < n; i++)
	{
		double xa, ya, ra, xb, yb, rb;
		std::cin >> xa >> ya >> ra >> xb >> yb >> rb;
		double d = hypot(xa - xb, ya - yb);
		if (d > ra + rb)
		{
			std::cout << 0 << std::endl;
		}
		else if (d >= abs(ra - rb))
		{
			std::cout << 1 << std::endl;
		}
		else
		{
			std::cout << 2 * (ra < rb ? -1 : 1) << std::endl;
		}
	}
	return 0;
}

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

#define equals(a, b) (fabs((a)-(b)) < EPS)
const double EPS = (1e-10);

class Point {
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(x*a, y*a);
    }
    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;
// ??????
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;
}

class Circle {
public:
    Point c;                    // ??????
    double r;                   // ??????
    Circle(Point c = Point(), double r = 0.0): c(c), r(r) {}
};


int intersect(Circle c1, Circle c2) {
    double d = (c2.c - c1.c).abs();

    // ????????£???????????´???
    if (d - (c1.r+c2.r) > EPS) {
        return 0;
    }

    if (c1.r > c2.r && c1.r-c2.r > d) {
        return 2;
    }
    if (c2.r > c1.r && c2.r-c1.r > d) {
        return -2;
    }

    return 1;
}

int main(void) {

    int N; cin >> N;
    for (int i = 0; i < N; i++) {
        Circle ca, cb;
        cin >> ca.c.x >> ca.c.y >> ca.r
            >> cb.c.x >> cb.c.y >> cb.r;

        cout << intersect(ca, cb) << endl;
    }

    return 0;
}

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

const long double EPS = 1e-17;

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

long double abs(long double x) {
  return (x > 0 ? x : -x);
}
/*
bool eq(long double x, long double y) {
  return abs(x - y) < EPS;
}*/

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

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

    long double d = sqrt((xa-xb)*(xa-xb) + (ya-yb)*(ya-yb));
    
    if (ra - rb > d + EPS) {
      cout << 2 << endl;
    } else if (rb - ra > d + EPS) {
      cout << -2 << endl;
    } else if (d > ra + rb + EPS) {
      cout << 0 << endl;
    } else {
      cout << 1 << endl;
    }
  }
}

C++: #include <iostream>
//#include <algorithm>
//#include "math.h"

#define EPS 1.e-12

using namespace std;

int main(){
	int count;
	double xa,ya,ra,xb,yb,rb;
	cin >> count;
	for(int i=0;i<count;i++){
		cin >> xa >> ya >> ra >> xb >> yb >> rb;
		double dist2 = (xa-xb)*(xa-xb)+(ya-yb)*(ya-yb);
		//		double dist = (xa-xb)*(xa-xb)+(xa-xb)*(xa-xb);
		//cout << dist2 << " " << (ra+rb)*(ra+rb) << endl;
		//cout << ((dist2 -(ra+rb)*(ra+rb))>0) << endl;
		if(dist2>(ra+rb)*(ra+rb)+EPS){
			cout << 0 << endl;
		}
		else if(dist2 >= (ra - rb)*(ra - rb)){
			cout << 1 << endl;
		}
		else if(ra>rb){
			cout << 2 << endl;
		}
		else{
			cout << -2 << 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;
    }
  }
}

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

const long double EPS = 1e-10;

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

long double abs(long double x) {
  return (x > 0 ? x : -x);
}
/*
bool eq(long double x, long double y) {
  return abs(x - y) < EPS;
}*/

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

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

    long double d = sqrt((xa-xb)*(xa-xb) + (ya-yb)*(ya-yb));
    
    if (ra - rb > d + EPS) {
      cout << 2 << endl;
    } else if (rb - ra > d + EPS) {
      cout << -2 << endl;
    } else if (d > ra + rb + EPS) {
      cout << 0 << endl;
    } else {
      cout << 1 << endl;
    }
  }
}

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

using namespace std;

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    double x1, y1, r1, x2, y2, r2;
    scanf("%lf %lf %lf %lf %lf %lf", &x1, &y1, &r1, &x2, &y2, &r2);
    double distance = sqrt(pow(x1 - x2, 2.0) + pow(y1 - y2, 2.0));
    if (distance > r1 + r2) {
      puts("0");
    } else if (distance + r2 < r1) {
      puts("2");
    } else if (distance + r1 < r2) {
      puts("-2");
    } else {
      puts("1");
    }
  }

  return 0;
}

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

int main() {
	int n;
	vector<int> r;
	cin >> n;
	for (int i; i<n; i++)
	{
		double xa,ya,ra,xb,yb,rb;
		cin >> xa >> ya >> ra >> xb >> yb >> rb;
		if (pow(xa-xb,2)+pow(ya-yb,2) > pow(ra+rb,2))
		{
			r.push_back(0);
		} else if (pow(xa-xb,2)+pow(ya-yb,2) < pow(ra-rb,2)) {
			(ra > rb) ? r.push_back(2) : r.push_back(-2);
		} else {
			r.push_back(1);
		}
	}
	for (int i=0; i<r.size(); i++)
	{
		cout << r[i] << endl;
	}
	return 0;
}

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

using namespace std;

typedef complex<double> Point;

//ツ円Aツつェツ円Bツづーツ環ョツ全ツづ可甘慊づ楪つゥツ板サツ津ィツつキツづゥ
bool includesCircle(const Point &ca, double ra, const Point &cb, double rb) {
    return norm(ca-cb) < pow(ra-rb, 2) && rb < ra;
}

//ツ円Aツづ円Bツつェツ古ーツづュツづづつ「ツづゥツつゥツ板サツ津ィツつキツづゥ
bool intersectsCircle(const Point &ca, double ra, const Point &cb, double rb) {
    return norm(ca-cb) <= pow(ra+rb, 2);
}

int main() {
    int N;
    cin >> N;
    while(N--) {
        Point ca, cb;
        double ra, rb;
        cin >> ca.real() >> ca.imag() >> ra >> cb.real() >> cb.imag() >> rb;
        if(includesCircle(ca, ra, cb, rb)) cout << 2 << endl;
        else if(includesCircle(cb, rb, ca, ra)) cout << -2 << endl;
        else if(intersectsCircle(ca, ra, cb, rb)) cout << 1 << endl;
        else cout << 0 << endl;
    }
    return 0;
}