Answer to Question #294568 in C++ for Shan

Question

10.Write a function which takes as input 4 points and tell whether these points

are the coordinates of Square, Rhombus, Rectangle, Parallelogram or

Quadrilateral. NOTE: Make separate functions for each case checking whether

its square / rhombus / rectangle / parallelogram. i-e (isSquare, isRhombus,

isRectangle, isParallelogram)

Sample Input:

P1 0 0

P2 1 0

P3 1 1

P4 0 1

Output: It’s a square

Answer 1

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


const double EPS=1e-12;
struct Point {
    double x;
    double y;
};


double distance(Point p1, Point p2) {
    return sqrt((p1.x-p2.x)*(p1.x-p2.x) + (p1.y-p2.y)*(p1.y-p2.y));
}


bool isEqual(double x, double y) {
    return abs(x-y) < EPS;
}



bool isSquare(Point p1, Point p2, Point p3, Point p4) {
    double s1 = distance(p1, p2);
    double s2 = distance(p2, p3);
    double s3 = distance(p3, p4);
    double s4 = distance(p4, p1);
    double d1 = distance(p1, p3);
    double d2 = distance(p2, p4);


    if (isEqual(s1, s2) && isEqual(s2, s3) && isEqual(s3, s4) &&
        isEqual(d1, d2) ) 
        return true;
    return false;
}


bool isRhombus(Point p1, Point p2, Point p3, Point p4) {
    double s1 = distance(p1, p2);
    double s2 = distance(p2, p3);
    double s3 = distance(p3, p4);
    double s4 = distance(p4, p1);
    double d1 = distance(p1, p3);
    double d2 = distance(p2, p4);


    if (isEqual(s1, s2) && isEqual(s2, s3) && isEqual(s3, s4) &&
        !isEqual(d1, d2) ) 
        return true;
    return false;
}



bool isRectangle(Point p1, Point p2, Point p3, Point p4) {
    double s1 = distance(p1, p2);
    double s2 = distance(p2, p3);
    double s3 = distance(p3, p4);
    double s4 = distance(p4, p1);
    double d1 = distance(p1, p3);
    double d2 = distance(p2, p4);


    if (isEqual(s1, s3) && isEqual(s2, s4) && isEqual(d1, d2) )
        return true;
    return false;
}


bool isParallelogram(Point p1, Point p2, Point p3, Point p4) {
    double s1 = distance(p1, p2);
    double s2 = distance(p2, p3);
    double s3 = distance(p3, p4);
    double s4 = distance(p4, p1);
    double d1 = distance(p1, p3);
    double d2 = distance(p2, p4);


    if (isEqual(s1, s3) && isEqual(s2, s4) && isEqual(d1, d2) )
        return true;
    return false;
}


int main() {
    Point p1, p2, p3, p4;

    cout << "P1 ";
    cin >> p1.x >> p1.y;
    cout << "P2 ";
    cin >> p2.x >> p2.y;
    cout << "P3 ";
    cin >> p3.x >> p3.y;
    cout << "P4 ";
    cin >> p4.x >> p4.y;
    cout << endl;

    if (isSquare(p1, p2, p3, p4)) {
        cout << "It's a square" << endl;
    }
    else if (isRhombus(p1, p2, p3, p4)) {
        cout << "It's a rhombus" << endl;
    }
    else if (isParallelogram(p1, p2, p3, p4)) {
        cout << "It's a parallelogram" << endl;
    }
    else  {
        cout << "It's common quadrilateral" << endl;
    }
}