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<iostream>
#include<math.h>
using namespace std;
int main() {
	int N,i;
	float xa, ya, ra, xb, yb, rb,r;
	cin >> N;
	for (i = 0; i < N; i++) {
		cin >> xa >> ya >> ra >> xb >> yb >> rb;
		r = pow(pow(xb - xa, (float)2.0) + pow(yb - ya, (float)2.0), (float)1.0/2);
		if (r > ra + rb) {
			cout << 0 << endl;
		}
		else if (r <= ra + rb) {
			if (ra > rb) {
				if (r <= ra - rb) {
					cout << 2 << endl;
				}
				else if (r > ra - rb) {
					cout << 1 << endl;
				}
			}
			else if (ra < rb) {
				if (r <rb - ra) {
					cout << -2 << endl;
				}
				else if (r > rb - ra) {
					cout << 1 << endl;
				}
			}
		}
	}
	return 0;
}

C++: #include <algorithm>
#include <iostream>
#include <cstdio>
#include <map>
#include <numeric>
#include <cmath>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <string.h>
using namespace std;

#define ISEQ(c) (c).begin(), (c).end()
typedef long long ll;

int main() {
  int n;
  cin >> n;
  double x[2], y[2], r[2];
  const double EPS = 1e-9;
  for (int z = 0; z < n; z++) {
    cin >> x[0] >> y[0] >> r[0];
    cin >> x[1] >> y[1] >> r[1];
    double cdif = sqrt((x[0]-x[1])*(x[0]-x[1]) - (y[0]-y[1])*(y[0]-y[1]));
    if (cdif+r[0]-r[1] < -EPS) cout << -2 << endl;
    else if (cdif+r[1]-r[0] < -EPS) cout << 2 << endl;
    else if (cdif-r[0]-r[1] < EPS) cout << 1 << endl;
    else cout << 0 << endl;
  }

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

const double EPS = 1e-8;

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, sq(ra)) or eq(d, sq(rb))) {
      cout << 1 << endl;
    } else if (d < sq(ra + rb)) {
      cout << 1 << endl;
    } else {
      cout << 0 << endl;
    }
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
/*{{{*/  //template
#define rep(i,n) for(int i=0;i<n;i++)
constexpr int INF = numeric_limits<int>::max()/2;
constexpr long long LINF = numeric_limits<long long>::max()/3;
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define sz(x) (int)(x).size()
#define debug(x) cerr<<#x<<":"<<x<<endl
#define debug2(x,y) cerr<<#x<<","<<#y":"<<x<<","<<y<<endl
//struct fin{ fin(){ cin.tie(0); ios::sync_with_stdio(false); } } fin_;
struct Double{ double d; explicit Double(double x) : d(x){} };
ostream& operator<<(ostream& os,const Double x){ os << fixed << setprecision(20) << x.d; return os; }
template<typename T> ostream& operator<<(ostream& os,const vector<T>& vec){ os << "["; for(const auto& v : vec){ os << v << ","; } os << "]"; return os; }
template<typename T,typename U> ostream& operator<<(ostream& os,const pair<T,U>& p){ os << "(" << p.first << ","<< p.second <<")"; return os; }
template<typename T> ostream& operator<<(ostream& os,const set<T>& st){ os<<"{"; for(T v:st) os<<v<<","; os <<"}"; return os; }
template<typename T,typename U> inline void chmax(T &x,U y){ if(y>x) x = y; }
template<typename T,typename U> inline void chmin(T &x,U y){ if(y<x) x = y; }
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
ll gcd(ll a,ll b){ if(b==0) return a; else return gcd(b,a%b); }
//constexpr double eps = 1e-14; 
constexpr double eps = 1e-10; 
constexpr ll mod = 1e9+7;
const int dx[]={1,0,-1,0} ,dy[] = {0,1,0,-1};
/*}}}*/

int main(){
    int N;
    cin >> N;

    rep(i,N){
        double x0,y0,r0,x1,y1,r1;
        cin >> x0 >> y0 >> r0 >> x1 >> y1 >> r1;

        double dx = x0 - x1;
        double dy = y0 - y1;
        double d = sqrt(dx*dx+dy*dy);

        if(d > r0 + r1){
            cout << 0 << endl;
        }else if(d + r1 < r0){
            cout << 2 << endl;
        }else if(d + r0 < r1){
            cout << -2 << endl;
        }else{
            cout << 1 << endl;
        }
    }
    return 0;
}

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

typedef complex<double> P;

int main() {
  int n;
  cin >> n;
  while(n--) {
    double ra,rb;
    double x1,y1,x2,y2;
    cin >> x1>>y1>>ra>>x2>>y2>>rb;
    P a(x1,y1), b(x2,y2);
    double d = abs(a-b);
    if (d<ra-rb) cout << 2;
    else if (d<rb-ra) cout << -2;
    else if (d<=ra+rb) cout << 1;
    else cout << 0;
    cout << endl;
  }
}

C++: #include<iostream>
#include<complex>
#define EPS 1e-15
using namespace std;

typedef complex<double>P;

int main(){
	int n;
	cin>>n;
	for(int i=0;i<n;i++){
		double ra,rb;
		P pa,pb;
		
		cin>>pa.real()>>pa.imag()>>ra;
		cin>>pb.real()>>pb.imag()>>rb;
		double d=abs(pa-pb);
		if(d+ra-rb<=EPS)cout<<-2<<endl;
		else if(d+rb-ra<=EPS)cout<<2<<endl;
		else if(d-ra-rb<=EPS)cout<<1<<endl;
		else cout<<0<<endl;
	}
}

C++: #include <iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>

using namespace std;

void Solution()
{
    int n;
    
    cin>>n;
    
    while(n--)
    {
        float xa, ya, ra;
        float xb, yb, rb;
        float d;
        
        cin>>xa>>ya>>ra>>xb>>yb>>rb;
        
        d = sqrt((xb - xa) * (xb - xa) + (yb - ya) * (yb - ya)); // distance of o1 and o2
        
        if ((d < ra - rb) && (ra > rb))
        {
            cout<<2<<endl;
        }
        else if ((d < rb - ra) && (ra < rb))
        {
            cout<<-2<<endl;
        }
        else if (fabs(d > ra - rb) && (d < ra + rb))
        {
            cout<<1<<endl;
        }
        else if (d > ra + rb)
        {
            cout<<0<<endl;
        }
//        else
//        {
//            cout<<1<<endl;
//        }
    }
}

int main()
{
    Solution();
    return 0;
}