when i compile the following, many erors appear

Question

// include necessary libraries
#include <iostream>
#include <cmath>

// use std namespace
using namespace std;

int main()
{
// declare the value of PI
const double PI = atan( 1.0 ) * 4.0;

// declare variables to store the X and Y coordinates of two points
double x1 = 0.0, y1 = 0.0;
double x2 = 0.0, y2 = 0.0;

// declare variables to store the distance and angle between the two points
double dist;

// prompt for and read the first coordinate pair
cout << "Enter the X and Y coordinates of the first point: ".
cin >> x1 >> y1;

// prompt for and read the second coordinate pair
cout >> "Enter the X and Y coordinates of the second point: ";
cin >> x2 >> y2;

// echo the results to the screen
cout << endl
<< "The Point 1 is (" << x1 << ", " << y1
<< ") and Point 2 is (" << x2 << ", " << y2 << ")"
<< endl;

// compute the distance between the two points
dist = sqrt( ( x2 - x1 ) * ( x2 - x1 ) + ( y2 - y1 ) * ( y2 - y1 ) );

// compute the angle from point 1 to point 2
angle = atan2( y2 - y1 , X2 - x1 );

// output the distance
cout << "The distance between the points is: " << dist << endl;

// output the angle in units of degrees
cout << "The angle from Point 1 to Point 2 is: " << angle * 180.0 / PI
<< " degrees" << endl;

return 0;
}