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

typedef long long int ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pair<int, int> > vii;
#define rrep(i, m, n) for(int (i)=(m); (i)<(n);  (i)++)
#define erep(i, m, n) for(int (i)=(m); (i)<=(n); (i)++)
#define  rep(i, n)    for(int (i)=0; (i)<(n);  (i)++)
#define rrev(i, m, n) for(int (i)=(n)-1; (i)>=(m); (i)--)
#define erev(i, m, n) for(int (i)=(n); (i)>=(m); (i)--)
#define  rev(i, n)    for(int (i)=(n)-1; (i)>=0; (i)--)
#define vrep(i, c)    for(__typeof((c).begin())i=(c).begin(); i!=(c).end(); i++)
#define  ALL(v)       (v).begin(), (v).end()
#define mp            make_pair
#define pb            push_back
template<class T, class S> inline bool minup(T& m, S x){ return m>(T)x ? (m=(T)x, true) : false; }
template<class T, class S> inline bool maxup(T& m, S x){ return m<(T)x ? (m=(T)x, true) : false; }

const int    INF = 1000000000;
const ll     MOD = 1000000007LL;
const double EPS = 1E-12;

template<typename T> T add(T x, T y){ if(abs(x+y) < EPS*(abs(x)+abs(y))) return 0; return x + y; }
template<typename T> inline bool semieq(T x, T y){ return abs(x - y) < EPS; }
template<typename T> inline bool semige(T x, T y){ return y - x < -EPS; }
template<typename T> inline bool semile(T x, T y){ return x - y < -EPS; }


struct Point : public complex<double>
{
public:
  Point() { this->real(0);  this->imag(0); }
  Point(const double& x, const double& y) { this->real(x);  this->imag(y); }
  Point(const complex<double> w)  { this->real(w.real());  this->imag(w.imag()); }
  inline double dot(Point p){ return (conj(*this) * p).real(); }  // ??????
  inline double det(Point p){ return (conj(*this) * p).imag(); }  // ??????
};

namespace std
{
  bool operator < (const Point& a, const Point& b)
  {
    return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);
  }
}
typedef vector<Point> Polygon;
#define currPoint(P, i) P[i]
#define nextPoint(P, i) P[(i+1)%P.size()]

struct Circle : Point
{
private:
  Point p;
  double r;

public:
  Circle(Point& p, double r) : p(p), r(r) {}
  Circle(double x, double y, double r) : p(Point(x, y)), r(r) {}
  inline Point center(){ return this->p; }
  inline double radius(){ return this->r; }
};

int circlesIntersection(Circle& A, Circle& B)
{
  double d = abs(A.center() - B.center());
  if(semile(d, A.radius() - B.radius())) return  1;  // B in A
  if(semile(d, B.radius() - A.radius())) return -1;  // A in B
  if(semieq(d, A.radius() - B.radius())) return  2;  // B in A????????\???
  if(semieq(d, B.radius() - A.radius())) return -2;  // A in B????????\???
  if(semige(d, A.radius() + B.radius())) return  3;  // ???????????????
  if(semieq(d, A.radius() + B.radius())) return -3;  // ?????\
  return 4;  // ????????£?????????
}

int n;
double x, y, r;

Point N(0.0, 0.0);

int main()
{
  cin >> n;

  while(n--){
    cin >> x >> y >> r;  Circle A(x, y, r);
    cin >> x >> y >> r;  Circle B(x, y, r);

    int res = circlesIntersection(A, B);
    if(res ==  1){ puts("2");   continue; }
    if(res == -1){ puts("-2");  continue; }
    if(res ==  3){ puts("0");   continue; }
    puts("1");
  }

  return 0;
}

C++: //include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>
#include <complex>
#include <math.h>

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<long, long> PLL;
typedef long long LL;
//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(long i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

const long double EPS = 1e-12;
const double INF = 1e12;


int main(){
	int n;
	cin>>n;
	long double xa,ya,ra,xb,yb,rb;
	REP(i,n){
		cin>>xa>>ya>>ra>>xb>>yb>>rb;
		long double d2=(xa-xb)*(xa-xb)+(ya-yb)*(ya-yb);
		if(ra>rb&&d2<(ra-rb)*(ra-rb)+EPS){
			cout<<"2"<<endl;
		}else if(ra<rb&&d2<(ra-rb)*(ra-rb)+EPS){
			cout<<"-2"<<endl;
		}else if(d2<(ra+rb)*(ra+rb)+EPS){
			cout<<"1"<<endl;
		}else{
			cout<<"0"<<endl;
		}
	}
	return 0;
}
/*
2
0.0 0.0 5.0 0.0 0.0 4.0
0.0 0.0 3.0 4.1 0.0 2.0
*/

C++: #include<stdio.h>
#include<math.h>
#include<stdlib.h>

int main()
{
	int n, i;
	double xa, ya, ra, xb, yb, rb;
	scanf("%d", &n);
	for (i = 0; i < n; i++)
	{
		scanf("%lf %lf %lf %lf %lf %lf", &xa, &ya, &ra, &xb, &yb, &rb);
		double lr = ra>rb ? ra : rb,
			sr = ra > rb ? rb : ra,
			distance = sqrt(pow(xa - xb, 2) + pow(ya - yb, 2));
		if (distance > ra + rb)
		{
			printf("0\n");
		}
		else if (distance < lr - sr)
		{
			if (lr = ra)printf("2\n");
			else printf("-2\n");
		}
		else
			printf("1\n");
	}
	return 0;
}

C++: #include <stdio.h>
#include <math.h>

int main()
{
	int n, t;
	double x1, y1, r1, x2, y2, r2;
	double d;

	scanf("%d", &n);

	for (int i = 0; i < n; i++) {
		scanf("%lf %lf %lf %lf %lf %lf", &x1, &y1, &r1, &x2, &y2, &r2);

		d = (x2-x1)*(x2-x1) + (y2-y1)*(y2-y1);
		if (d >= (r1 + r2)*(r1 + r2)) t = 0;
		else if (d == (r1 + r2)*(r1 + r2) || d == (r1 - r2)*(r1 - r2)) t = 1;
		else if (d < (r2-r1)*(r2-r1)){
			if (r2 < r1) t = 2;
			else if (r2 > r1) t = -2;
		}

		printf("%d\n", t);
	}

	return 0;
}

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

using namespace std;

int main() {
	int n, ans;
	float x1, y1, r1, x2, y2, r2, dis, diff;

	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x1 >> y1 >> r1 >> x2 >> y2 >> r2;
		dis = hypot(x2 - x1, y2 - y1);
		ans = 0;

		if (dis + r2 < r1) { ans = 2; }
		else if (dis + r1 < r2) { ans =  -2; }
		else if (r1 + r2 >= dis) { ans = 1; }

		cout << ans << endl;
	}
	return 0;
}