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 <cstdio>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <climits>
#include <ctime>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <set>
#include <map>
#include <iostream>
#include <deque>
#include <complex>
#include <string>
#include <iomanip>
#include <sstream>
#include <bitset>
#include <valarray>
#include <iterator>
using namespace std;
typedef long long int ll;
typedef unsigned int uint;
typedef unsigned char uchar;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

#define REP(i,x) for(int i=0;i<(int)(x);i++)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();i++)
#define RREP(i,x) for(int i=((int)(x)-1);i>=0;i--)
#define RFOR(i,c) for(__typeof((c).rbegin())i=(c).rbegin();i!=(c).rend();i++)
#define ALL(container) container.begin(), container.end()
#define RALL(container) container.rbegin(), container.rend()
#define SZ(container) ((int)container.size())
#define mp(a,b) make_pair(a, b)
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
os<<"["; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"]"; return os;
}
template<class T> ostream& operator<<(ostream &os, const set<T> &t) {
os<<"{"; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"}"; return os;
}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}
template<class S, class T> pair<S,T> operator+(const pair<S,T> &s, const pair<S,T> &t){ return pair<S,T>(s.first+t.first, s.second+t.second);}
template<class S, class T> pair<S,T> operator-(const pair<S,T> &s, const pair<S,T> &t){ return pair<S,T>(s.first-t.first, s.second-t.second);}

const int INF = 1<<28;
const double EPS = 1e-8;
const int MOD = 1000000007;

namespace geom{
#define X real()
#define Y imag()
	
	typedef double R;
	typedef complex<R> P;
	istream& operator>>(istream &is, P &p) {
		double x, y;
		is >> x >> y;
		p = P(x, y);
		return is;
	}
	struct L : public vector<P>{
		L(const P &p1, const P &p2){this->push_back(p1);this->push_back(p2);}
		friend istream& operator>>(istream &is, L &l) {
			P p1, p2;
			is >> p1 >> p2;
			l = L(p1, p2);
			return is;
		}
	};
	inline int sig(double x) { return (abs(x) < EPS ? 0 : x > 0 ? 1 : -1); }
	inline R norm(const P &p){return p.X*p.X+p.Y*p.Y;}
	inline R inp(const P& a, const P& b){return (conj(a)*b).X;}
	inline R outp(const P& a, const P& b){return (conj(a)*b).Y;}
	inline P unit(const P& p){return p/abs(p);}
	inline P proj(const P &s, const P &t){return t*inp(s, t)/norm(t);}
	inline P proj(const P &s, const L &t){return t[0] + proj(s-t[0], t[1]-t[0]);}
	inline bool sp_intersect(const L &s, const P &p){return !sig(abs(s[0]-p) + abs(s[1] - p) - abs(s[0] - s[1]));}
	
	struct C : public P{
		double r;
		friend istream& operator>>(istream &is, C &c) {
			operator>>(is, (P &)c);
			is >> c.r;
			return is;
		}
	};
	
	struct G : public vector<P>{
		enum {OUT, IN, ON};
		P &at(int i){return (*this)[i];}
		bool contains(const P &p){
			R sum = .0;
			REP(i, size()){
				if(sp_intersect(L(at(i), at((i+1)%size())), p)) return ON;	// online
				sum += arg((at(i) - p) / (at((i+1)%size()) - p));
			}
			return sig(sum) ? IN : OUT;
		}
		
		R area(){
			R sum = 0;
			REP(i, size()) sum += outp(at(i), at((i+1)%size()));
			return abs(sum / 2.);
		}
	};
};
using namespace geom;

int n;

int main(){
	ios::sync_with_stdio(false);
	int T;
	cin >> T;
	REP(t, T){
		C a, b;
		cin >> a >> b;
		int ans;
		if(abs(a-b) > a.r + a.r + EPS) ans = 0;
		else if(abs(a-b)+b.r < a.r - EPS) ans = 2;
		else if(abs(a-b)+a.r < b.r - EPS) ans = -2;
		else ans = 1;
		cout << ans << endl;
	}
	return 0;
}

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

class Point{
public:
    double x,y;
    
    Point(double xx,double yy){
        x = xx;
        y = yy;
    }
};

double distance(Point p1,Point p2){
    return sqrt(pow(p1.x-p2.x,2)+pow(p1.y-p2.y,2));
}

struct data1{
    double x,y,r;
} circle1;

struct data2{
    double x,y,r;
} circle2;

int main(){
    int n;
    
    cin >> n;
    while(n--){
        cin >> circle1.x >> circle1.y >> circle1.r;
        cin >> circle2.x >> circle2.y >> circle2.r;
        
        Point p1(circle1.x,circle1.y),p2(circle2.x,circle2.y);
        double d = distance(p1,p2);
        
        if(circle1.r + circle2.r < d) cout << "0" << endl;
        else if(circle2.r + d < circle1.r) cout << "2" << endl;
        else if(circle1.r + d < circle2.r) cout << "-2" << endl;
        else cout << "1" << endl;
    }
    
    return 0;
}

C++: #include <algorithm>
#include <cmath>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <cassert>
#include <functional>

using namespace std;

#define LOG(...) printf(__VA_ARGS__)
//#define LOG(...)
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define RSORT(c) sort((c).rbegin(),(c).rend())
#define CLR(a) memset((a), 0 ,sizeof(a))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int dx[] = { -1, 0, 1, 0 }; const int dy[] = { 0, 1, 0, -1 };
struct en{
	pair<double, double> pos;
	double r;
};
int main() {
	int n;
	cin >> n;
	while (n--){
		en e1,e2;
		cin >> e1.pos.first >> e1.pos.second >> e1.r >> e2.pos.first >> e2.pos.second >> e2.r;
		double dis = hypot(e1.pos.first - e2.pos.first, e1.pos.second - e2.pos.second);
		if (e1.r>e2.r&&dis + e2.r<e1.r)cout << 2 << endl;
		else if (e1.r<e2.r&&dis+e1.r<e2.r)cout << -2 << endl;
		else if (e1.r + e2.r>dis)cout << 1 << endl;
		else cout << 0 << endl;
	}
}

C++: #include<iostream>
#include<cmath>
int main()
{
	int n;
	std::cin >> n;
	for (int i = 0; i < n; i++)
	{
		long double xa, ya, ra, xb, yb, rb;
		std::cin >> xa >> ya >> ra >> xb >> yb >> rb;
		long double d = hypot(xa - xb, ya - yb);
		if (d < std::abs(ra - rb))
		{
			std::cout << 2 * (ra < rb ? -1 : 1) << std::endl;
		}
		else if (d <= ra + rb)
		{
			std::cout << 1 << std::endl;
		}
		else
		{
			std::cout << 0 << std::endl;
		}
	}
	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) || d == (r2 - r1)*(r2 - r1)) t = 1;
		else if (d < (r2-r1)*(r2-r1)){
			if (r2 < r1) t = 2;
			else if (r2 > r1) t = -2;
		}else if (d >= (r1 + r2)*(r1 + r2)) t = 0;

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

	return 0;
}