(Distance Between Points) Write function distance that calculates the distance between two points (x1, y1) and (x2, y2). All numbers and return values should be of type double.

Question

What will be an ideal response?

Answer 1

```
// Calculate distance between 2 points.
#include
#include
#include
using namespace std;

double distance( double, double, double, double ); // function prototype

int main()
{
double x1; // x coordinate of first point
double y1; // y coordinate of first point
double x2; // x coordinate of second point
double y2; // y coordinate of second point

// prompt for first point coordinates
cout << "Enter the first point: ";
cin >> x1 >> y1;

// prompt for second point coordinates
cout << "Enter the second point: ";
cin >> x2 >> y2;

// calculate and display distance
cout << fixed << "Distance between (" << setprecision( 1 ) << x1
<< ", " << y1 << ") and (" << x2 << ", " << y2 << ") is "
<< distance( x1, y1, x2, y2 ) << endl;
} // end main
// distance calculates distance between 2 points
// given by (a1, b1) and (a2, b2)
double distance( double a1, double b1, double a2, double b2 )
{
return sqrt( pow( a1 - a2, 2 ) + pow( b1 - b2, 2 ) );
} // end function distance
```