Go: package main

import (
        "fmt"
        "math"
)

func main() {
        var n int
        fmt.Scanf("%d", &n)
        for i := 0; i < n; i++ {
                var ax, ay, ar, bx, by, br float64
                fmt.Scanf("%f %f %f %f %f %f", &ax, &ay, &ar, &bx, &by, &br)

                d := math.Sqrt((bx-ax)*(bx-ax) + (by-ay)*(by-ay))
                if d <= ar + br {
                        if ar > br {
                                if ar > br + d {
                                        fmt.Println("2")
                                } else {
                                        fmt.Println("1")
                                }
                        } else {
                                if br > ar + d {
                                        fmt.Println("-2")
                                } else {
                                        fmt.Println("1")
                                }
                        }
                } else {
                        fmt.Println(0)
                }
        }
}

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 x - y > -EPS; }
template<typename T> inline bool semile(T x, T y){ return y - x > -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("1");   continue; }
    if(res ==  3){ puts("0");   continue; }
  }

  return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <stack>
#include <set>
#include <cmath>
#include <algorithm>
using namespace std;

int main(){
	double xa , ya , ra , xb , yb , rb;
	double ab;
	int n;
	cin >> n;
	for(int i=0 ; i<n ; ++i){
		cin>> xa >> ya >> ra >> xb >> yb >> rb;
	ab=sqrt((xa-xb)*(xa-xb)+(ya-yb)*(ya-yb));
	if(ra-ab>rb) cout << 2 << endl;
	else if (rb-ab>ra) cout << -2 << endl;
	else if (ab>ra+ra) cout << 0 << endl;
	else cout << 1 << endl; 
	}
	return 0; 
}

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

using namespace std;

inline double sq (double a) {
    return a * a;
}

inline double dist (double x1, double y1, double x2, double y2) {
    return sqrt(sq(x1 - x2) + sq(y1 - y2));
}

int main (void) {
    int N;
    cin >> N;
    while (N--) {
        double xa, ya, ra, xb, yb, rb;
        cin >> xa;
        cin >> ya;
        cin >> ra;
        cin >> xb;
        cin >> yb;
        cin >> rb;
        double d = dist(xa, ya, xb, yb);
        int s;
        if (d + rb < ra) s = 2;
        else if (d + ra < rb) s = -2;
        else if (d < ra + rb) s = 1;
        else s = 0;
        cout << s << endl;
    }
    return 0;
}

C++: // includes
#include <cstdio>
#include <cstdint>
#include <iostream>
#include <iomanip>
#include <string>
#include <queue>
#include <stack>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <algorithm>
#include <utility>
#include <functional>
#include <cmath>
#include <climits>
#include <bitset>

// macros
#define ll long long int
#define pb push_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a); i<(b);++i)
#define rep(i, n) FOR(i, 0, n)

using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;

// solve

int main(int argc, char const* argv[])
{
  int n;
  cin >> n;
  double x[2], y[2], r[2];
  rep(i, n){
    rep(j, 2){
      cin >> x[j] >> y[j] >> r[j];
    }
    double dis = sqrt((x[1] - x[0]) * (x[1] - x[0]) + (y[1] - y[0]) * (y[1] - y[0]));
    if(dis > r[0] + r[1])cout << 0 << endl;
    else if(abs(r[0] - r[1]) <= dis){
      cout << 1 << endl;
    }else{
      if(r[0] > r[1]){
        cout << 2 << endl;
      }else{
        cout << - 2 << endl;
      }
    }
  }
	return 0;
}

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

int main()
{
	int n;
	cin >> n;
	for (int i = 0; i < n; i++){
		double xa, ya, ra, xb, yb, rb;
		cin >> xa >> ya >> ra >> xb >> yb >> rb;
		double d = (xb - xa) * (xb - xa) + (yb - ya) * (yb - ya);
		if (d < rb - ra){
			cout << -2 << endl;
		}
		else if (d < ra - rb){
			cout << 2 << endl;
		}
		else if (d > ra + rb){
			cout << 0 << endl;
		}
		else{
			cout << 1 << endl;
		}
	}
	return 0;
}