C++ Exercises: Check whether two straight lines AB and CD are orthogonal or not

Last update on August 11 2025 12:58:00 (UTC/GMT +8 hours)

Orthogonal Lines Check

There are four different points on a plane: A(x1, y1), B(x2, y2), C(x3, y3) and D(x4, y4).
Write a C++ program to check whether two straight lines AB and CD are orthogonal or not.
Input:
0 6
5 6
3 8
3 2
Output:
yes

Visual Presentation:

C++ Exercises: Check whether two straight lines AB and CD are orthogonal or not

Sample Solution:

C++ Code :

#include <iostream>
using namespace std;

int main(void) {
    double x[4], y[4]; // Arrays to store x and y coordinates of points

    // Continuously take input for x and y coordinates until EOF
    while (cin >> x[0] >> y[0]) {
        // Input coordinates of points
        for (int i = 1; i < 4; i++) {
            cin >> x[i] >> y[i];
        }

        // Check if vectors AB and CD are orthogonal using dot product
        if ((x[1] - x[0]) * (x[3] - x[2]) + (y[3] - y[2]) * (y[1] - y[0]) == 0) {
            cout << "Yes, AB and CD are orthogonal." << endl; // Output if AB and CD are orthogonal
        } else {
            cout << "Yes, AB and CD are not orthogonal." << endl; // Output if AB and CD are not orthogonal
        }
    }
    return 0;
}

Sample Output:

Input number: 0 6
5 6
3 8
3 2
Yes, AB and CD are orthogonal.

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to check whether two lines defined by points A, B and C, D are perpendicular using vector dot product.
Write a C++ program that reads coordinates for four points and determines if line AB is orthogonal to line CD with appropriate precision.
Write a C++ program to determine if two lines are perpendicular by calculating the slopes and verifying that their product is -1.
Write a C++ program that uses user-defined functions to check the orthogonality of two lines based on coordinate geometry.

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