отрезки

#include<iostream>
#include <algorithm>

using namespace std;

struct otrezok
{
  int x = 0, y = 0, length = 0;

  void perestanovka ()
  {
    if (x > y)
     swap(x, y);
  }
  void shet ()
  {
    if (x != 0 && y != 0)
     length = y - x +1;
    else if (x == y && x == 0)
     length = 0;
  }
};

int main()
{
  otrezok A, B, result;
  cin >> A.x >> A.y >> B.x >> B.y;

  A.perestanovka();
  B.perestanovka();

  //cout << A.x << " " <<  A.y << " " << B.x << " " << B.y;
  if (A.x >= B.x && A.x <= B.y)
    {
      result.x = A.x;
      if (A.y >= B.x && A.y <= B.y)
       result.y = A.y;
      if (A.y >= B.x && A.y >= B.y)
       result.y = B.y;
    }
  else if (B.x >= A.x && B.x <= A.y)
    {
      result.x = B.x;
      if (B.y >= A.x && B.y <= A.y)
       result.y = B.y;
      if (B.y >= A.x && B.y >= A.y)
       result.y = A.y;
    };

result.shet();

cout << result.length;
}