c + + 2点之间的距离分配

Question

people, i have a question regarding one of my programming assignment. the assignment is Write a complete C++ program called closest.cpp that reads three points p1 = (x1, y1), p2 = (x2, y2) and p3 = (x3, y3) from the standard input in the following format. the functions I created are mandatory for the project my teacher wanted us to use them in the main program exactly how i have it set up. my program compiles but it does not seem to get the input from the user each time I run my program it outputs

x1 y1
x2 y2
x3 y3

1.0 3.0
1.5 7.2
4.0 2.0
The three points are:
  0.000      0.000 
  0.000      0.000 
  0.000      0.000 
The closest two points are:
 0.000      0.000
 0.000      0.000 

The distance between those two points is:      0.000
The closest two points are:
 0.000      0.000
 0.000      0.000 

The distance between those two points is:      0.000
The closest two points are:
 0.000      0.000
 0.000      0.000 

The distance between those two points is:      0.000

when it should print out this instead

The three points are:
 1.000      3.000
 1.500      7.200
 4.000      2.000

The closest two points are:
 1.000      3.000
 4.000      2.000

The distance between those two points is:      3.162

this is the correct output

#include <cstdio>
#include <cmath>
using namespace std;

void displayInput(double x1, double y1, double x2, double y2, double x3, 
double y3)
{
printf("The three points are:\n %10.3f %10.3f \n %10.3f %10.3f \n %10.3f 
%10.3f \n",
x1, y1, x2, y2, x3, y3);
}


double distance(double x1, double y1, double x2, double y2)
{
double value = pow (x1 - x2, 2) + pow(y1 - y2, 2);
return sqrt(value);
}

void showOutput(double x1, double y1, double x2, double y2, double d)
{
printf("The closest two points are:\n%10.3f %10.3f\n%10.3f %10.3f \n"
"\nThe distance between those two points is: %10.3f\n",
x1, y1, x2, y2,d);
}

void consider(double x1, double y1, double x2, double y2, double x3, double 
y3)
{
double ans1, ans2, ans3;
ans1 = distance(x1, y1, x2, y2);
ans2 = distance(x1, y1, x3, y3);
ans3 = distance(x2, y2, x3, y3);

 if (ans1 <= ans2 && ans1 <= ans3)
  {
   showOutput(x1, y1, x2, y2, ans1);
  }
}


int main()
{
double x1, x2, y1, y2, x3, y3;

scanf("%f%f%f%f%f%f", &x1, &y1, &x2, &y2, &x3, &y3);

displayInput(x1, y1, x2, y2, x3, y3);

consider(x1, y1, x2, y2, x3, y3);
consider(x1, y1, x3, y3, x2, x2);
consider(x2, y2, x3, y3, x1, y1);
return 0;
}

Answer 1

After you changed the format of scanf to "%lf%lf%lf%lf%lf%lf" you might as well correct this line:

consider(x1, y1, x3, y3, x2, x2);
                            ^^^^ //<-- should be y2, no?

Copypasta is unforgiving!

Answer 2

Your comparison function doesn't account for all combinations.
Here is an example:

double shortest_distance = ans1;
double shortest_x1 = x1;
double shortest_y1 = y1;
double shortest_x2 = x2;
double shortest_y2 = y2;

if (ans2 < shortest_distance)
{
  shortest_distance = ans2;
  shortest_x1 = x1;
  shortest_y1 = y1;
  shortest_x2 = x3;
  shortest_y2 = y3;
}
if (ans3 < shortest_distance)
{
  shortest_distance = ans3;
  shortest_x1 = x2;
  shortest_y1 = y2;
  shortest_x2 = x3;
  shortest_y2 = y3;
}
showOutput(shortest_x1, shortest_y1,
           shortest_x2, shortest_y2,
           shortest_distance);