c++提示用户输入两个点的坐标，然后计算并输出这两个点之间的距离

提示用户输入两个点的坐标，然后计算并输出这两个点之间的距离。两点坐标为（x1,y1), (x2,y2)，距离为对应坐标差的平方和，再开平方。输出的距离保留4位小数。
求解答 为什么计算结果不正确

#include 
#include
#include
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char** argv) {
    cout<<"Please input the coordinates of two points:"<"point 1(x,y):"<"point 2(x,y):"<double x1,x2,y1,y2,distance;
    cin>>(x1,y1)>>(x2,y2);
    distance=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
    cout<<"This distance is:"<setprecision(4)<return 0;
}

#include <cmath>
#include <iomanip>
#include <iostream>

using namespace std;

int main(int argc, char **argv) {
  double x1, x2, y1, y2, distance;
  char ch;
  cout << "Please input the coordinates of two points:" << endl;
  cout << "point 1(x,y): ";
  cin >> ch >> x1 >> ch >> y1 >> ch;
  cout << "point 2(x,y): ";
  cin >> ch >> x2 >> ch >> y2 >> ch;
  distance = sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
  cout << "This distance is:" << fixed << setprecision(4) << distance << endl;
  return 0;
}

$ g++ -Wall main.cpp
$ ./a.out
Please input the coordinates of two points:
point 1(x,y): (1,1)
point 2(x,y): (2,2)
This distance is: 1.4142

#include <iostream>
#include<math.h>
#include<iomanip>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
 
int main(int argc, char** argv) {
    cout<<"Please input the coordinates of two points:"<<endl;
    
    
    double x1,x2,y1,y2,distance;
    cout<<"point 1(x,y):"<<endl;
    cout<<"point 1 X:"<<endl;
    cin>> x1 ;
    cout<<"point 1 Y:"<<endl;
    cin>> y1;
    cout<<"point 2(x,y):"<<endl;
    cout<<"point 2 X:"<<endl;
    cin>> x2 ;
    cout<<"point 2 Y:"<<endl;
    cin>> y2;
    distance=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
    cout<<"This distance is:"<<fixed<<setprecision(4)<<distance<<endl;
    return 0;
}