Check if it's a square or rectangle [closed]

Question

I want to check in my if and else if statement if the inputs form a square or a rectangle, now my if and else if statements seems to be unreadable, now I'm thinking of ways to improve it.

  /* input are angles in degrees, 1st side is parallel to 3rd side, 2nd side is parallel to 4th side*/    
  static void Main(string[] args)
  {
     Console.Write("Input first: ");
     int first = int.Parse(Console.ReadLine());

     Console.Write("Input second: ");
     int second = int.Parse(Console.ReadLine());

     Console.Write("Input third: ");
     int third = int.Parse(Console.ReadLine());

     Console.Write("Input fourth: ");
     int fourth = int.Parse(Console.ReadLine());

     // all sides are equal
     // logic for if and else-if, needs codereview for improvement
     if (first == second && first == third && first == fourth && second == third && second == fourth && third == fourth)
     {
        Console.WriteLine("Square");
     }
     else if (first != second && first == third && first != fourth && second != third && second == fourth )
     {
        Console.WriteLine("Rectangle");
     }
     else
     {
        Console.WriteLine("Not a square nor a rectangle");
     }

     Console.ReadKey();
  }

Answer 1

Simplify the if by just doing

if (first == second && second == third && third == fourth)
{....}

You said the inputs are degrees, now it’s been awhile since geometry but squares and rectangles are determined by length of side, not angle degree. Both are 4 sided objects so every angle is the same (unless you’re talking about something like a trapezoid, rhombus).

Answer 2

1. Remove comments that make lies. (Some goorus claim that it is a reason to never make any comments at all -after code changes they will eventually always start to lie)

        /* input are angles in degrees, 1st side is parallel to 3rd side, 2nd side is parallel to 4th side*/
   

2. Square is just a special case of the rectangle. Using this property you can simplify your if statement by:

        if (first == third && second == fourth)
        {
           if(first == second)
           {
              Console.WriteLine("Square");
           }
           else
           {
              Console.WriteLine("Rectangle");
           }
        }
        else
        {
           Console.WriteLine("Not a square nor a rectangle");
        }
   

3. Optionally you can generalize gathering input:

        int[] sideLengths = new int[4];
        for(int sideNumber = 0; sideNumber < 4; ++sideNumber)
        {
           Console.WriteLine($"Input {sideNumber+1}: ");
           sideLengths[sideNumber] = int.Parse(Console.ReadLine());
        }
   

4. Optionally you can validate user input (if it is an integer, etc...). After applying 3rd step it would be easy

Answer 3

I agree with @mpasko256, try to be generic when you can, specific when you have to.

However, your code is misleading and need some improvements:

• As others said, your comments are misleading: you play with lengths here (or you should) not degrees.
• If you give your program to your beloved grandmother, she'll not understand what to do. Give some (basic) information to your user (Purpose, what to type, ...)
• If we remove your comments (misleading, as i said), we have to mentally do some gymnastics to understand 'first', 'second', 'third' and 'fourth'. Why just not naming them 'top', 'right', 'bottom' and 'left', that's more expressive.
• try to splits functionalities into reusable functions

Then, you can try to train your skills and enhancing your programe:

• asking the number of sides
• asking the degrees between sides
• etc

Answer 4

This code is not correct. You cannot tell if the shape is a square, by only assessing the angles. All squares and rectangles have four angles of 90 degrees. And a square is a rectangle.

You will need At least two angles (both need to be 90 degrees) AND the length of three sides (all three need to be the same) to determine if the shape is a square. (And off course the confirmation that there are only four angles in total. I assume that you take this implicitly.)

For now, you can only determine if it is a rectangle. And you don't even need all four corners for it. If three out of four angles are 90 degrees, the fourth one will be 90 degrees as well.

if (first == 90 && second == 90 && third == 90)
    Console.WriteLine("Rectangle. Maybe even a square");
else
    Console.WriteLine("Not a square nor a rectangle");