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++: /* {{{ Shinobu kawaii */
/*
  ______   __        _                  __                 
.' ____ \ [  |      (_)                [  |                
| (___ \_| | |--.   __   _ .--.   .--.  | |.--.   __   _   
 _.____`.  | .-. | [  | [ `.-. |/ .'`\ \| '/'`\ \[  | | |  
| \____) | | | | |  | |  | | | || \__. ||  \__/ | | \_/ |, 
 \______.'[___]|__][___][___||__]'.__.'[__;.__.'  '.__.'_/ 
                                                           
*/
/* }}} */

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

// #define int long long

/* cpp template {{{ */

/* short */
#define pb push_back
#define mp make_pair
#define print(x) cout << x << '\n'
#define Fi first
#define Se second

/* REPmacro */
#define REPS(i, a, n) for (int i = (a); i < (n); i++)
#define REP(i, n) for (int i = 0; i < (n); i++)
#define RREP(i, n) for (int i = 1; i <= (n); i++)
#define DEPS(i, a, n) for (int i = (a); i >= n; i--)
#define DEP(i, n) for (int i = (n); i >= 0; i--)

/* typedef */
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vector<int> > vii;
typedef pair<int, int> pii;

/* const */
const int INF = 999999999;
const double EPS = 1e-9;
const int dx[] = {0, 1, 0, -1, 1, -1, 1, -1}, dy[] = {1, 0, -1, 0, 1, -1, -1, 1};

/* func */
inline bool is_uruu(int y) {return y % 4 == 0 && y % 100 != 0 || y % 400 == 0;}
inline bool inside(int y, int x, int H, int W) {return y >= 0 && x >= 0 && y < H && x < W;}

/* }}} */

#define sq(x) ((x) * (x))

signed main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n;
  cin >> n;

  while (n--){
    double xa, ya, ra, xb, yb, rb;
    cin >> xa >> ya >> ra >> xb >> yb >> rb;
    double d = sqrt(sq(xa - xb) + sq(ya - yb));

    if (d < fabs(ra - rb)){
      print("2");
    } else if (d < fabs(rb - ra)){
      print("-2");
    } else if (d <= ra + rb){
      print("1");
    } else {
      print("0");
    }
  }

  return 0;
}

C++: #include<iostream>
#include<cmath>
using namespace std;
int main() {
	int l[51];
	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 distance = sqrt((xa - xb)*(xa - xb) + (ya - yb)*(ya - yb));
		if (distance <= abs(ra - rb)) {
			if (ra > rb)l[i] = 2;else l[i] = -2;
		}
		else if (distance > ra + rb)l[i] = 0;
		else l[i] = 1;
	}
	for (int i = 0; i < n; i++)
		cout << l[i] << endl;
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
  
#define REP(i,s,n) for(int i=s;i<n;++i)
#define rep(i,n) REP(i,0,n)
#define SORT(c) sort((c).begin(),(c).end())
#define IINF INT_MAX
#define LLINF LLONG_MAX
  
typedef long long ll;
typedef pair<int, int> ii;
 
#define EPS 1e-8
 
int main(){
 
    int n;
    cin >> n;
    while(n--){
        double xa, ya, ra, xb, yb, rb;
        cin >> xa >> ya >> ra >> xb >> yb >> rb;
        double d = sqrt((xa - xb) * (xa - xb) + (ya - yb) * (ya - yb));
        if(d > ra + rb) cout << 0 << endl;
        else if(d < fabs(ra - rb)){
            if(ra > rb) cout << 2 << endl;
            else cout << -2 << endl;
        }
        else cout << 1 << endl;
    }
    return 0;
}

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

using namespace std;

struct Vector
{
	double x;
	double y;
};

istream& operator>>(istream& stream, Vector& p)
{
	return stream >> p.x >> p.y;
}

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

	while(length-- > 0)
	{
		Vector a, b;
		double ra, rb;
		cin >> a >> ra >> b >> rb;
		double dist = sqrt((b.x - a.x) * (b.x - a.x) + (b.y - a.y) * (b.y - a.y));

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

	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <climits>
#include <string>
#include <vector>
#include <cmath>

using namespace std;

#define rep(i, n)      for (int i=0; i<int(n); i++)
#define rep3(i, s, n)  for (int i=int(s); i<int(n); i++)
#define rev_rep(i, n)  for (int i=int(n)-1; i>=0; i-=1)

int N;

int main() {
  cin >> N;
  rep(i, N) {
    double xa, ya, ra, xb, yb, rb;
    cin >> xa >> ya >> ra >> xb >> yb >> rb;
    double dist = sqrt((xa-xb)*(xa-xb) + (ya-yb)*(ya-yb));
    int ans = 0;
    if (dist < ra+rb) ans = 1;
    if (ra > rb && dist <= ra-rb) ans =  2;
    if (ra < rb && dist <= rb-ra) ans = -2;
    cout << ans << "\n";
  }
  return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <vector>
#include <string>
#include <sstream>
#include <algorithm>
#include <complex>
#include <map>
using namespace std;
typedef long long ll;
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<VI> VVI;
#define rep(i,n) for (int i=0; i < (n); i++)

typedef double D;      // 座標値の型。doubleかlong doubleを想定
typedef complex<D> P;  // Point
typedef pair<P, P> L;  // Line
typedef vector<P> VP;
const D EPS = 1e-9;    // 許容誤差。問題によって変える
#define X real()
#define Y imag()
#define LE(n,m) ((n) < (m) + EPS)
#define GE(n,m) ((n) + EPS > (m))
#define EQ(n,m) (abs((n)-(m)) < EPS)

// 内積　dot(a,b) = |a||b|cosθ
D dot(P a, P b) {
  return (conj(a)*b).X;
}
// 外積　cross(a,b) = |a||b|sinθ
D cross(P a, P b) {
  return (conj(a)*b).Y;
}

// 2円の共通接線。返される各直線に含まれる頂点は円との接点となる
vector<L> tangentLines(P a, D ar, P b, D br) {
  vector<L> ls;
  D d = abs(b-a);
  rep (i,2) {
    D sin = (ar - (1-i*2)*br) / d;
    if (!LE(sin*sin, 1)) break;
    D cos = sqrt(max(1 - sin*sin, 0.0));
    rep (j,2) {
      P n = (b-a) * P(sin, (1-j*2)*cos) / d;
      ls.push_back(L(a + ar*n, b + (1-i*2)*br*n));
      if (cos < EPS) break;  // 重複する接線を無視（重複していいならこの行不要）
    }
  }
  return ls;
}

int main() {
  int n;
  cin >> n;
  D xa, ya, ra, xb, yb, rb;
  rep (_,n) {
    cin >> xa >> ya >> ra >> xb >> yb >> rb;
    
    vector<L> ls = tangentLines(P(xa,ya), ra, P(xb,yb), rb);
    if (ls.size() == 4) cout << 0;
    else if (ls.size() == 0) cout << ((xa < xb) ? -2 : 2);
    else cout << 1;
    cout << endl;
  }
  return 0;
}

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

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

C++: #include<iostream>
using namespace std;
int main(){
	int c;
	double ax,ay,ar,bx,by,br;
	cin>>c;
	for(int i=0;i<c;i++){
		cin>>ax>>ay>>ar>>bx>>by>>br;
		if((ax+ar>bx+br&&ax-ar<bx-br) && (ay+ar>by+br&&ay-ar<by-br))
			cout<<"2";
		else if((bx+br>ax+ar&&bx-br<ax-ar) && (by+br>ay+ar&&by-br<ay-ar))
			cout<<"-2";
		else if(!(ax+ar>bx-br&&bx+br>ax-ar)&&!(bx+br>ax-ar&&ax+ar>bx-br))
			cout<<"0";
		else cout<<"1";
	cout <<endl;	
	}				
}

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

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