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

## C++ Basic: Exercise-77 with Solution

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:**

**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: **

**C++ Code Editor:**

**Previous:** Write a C++ program that accept an integer (n) from the user and outputs the number of combinations that express n as a sum of two prime numbers.

**Next:** Write a C++ program to sum of all positive integers in a sentence.

**What is the difficulty level of this exercise?**

**Weekly Trends and Language Statistics**- Weekly Trends and Language Statistics