How to create a switch.. case with value ranges?

Question

If a total of days is over 30 and under 60, I do something. If it’s over 60 and under 90 I do something else and so on. How do I do this case? Did the case is the best option?

Answer 1

Good afternoon,

Very interesting question, I just came across this problem in a course I’m doing.

I saw the solution of a colleague here in the forum in the Java language:

class Main {
    public static void main (String[] args) {
        int x = 534;
        switch (x / 200) {
            case 0:
                System.out.println("entre 0 e 199");
                break;
            case 1:
                System.out.println("entre 200 e 399");
                break;
            case 2:
                System.out.println("entre 400 e 599");
                break;
            default:
                System.out.println("600 ou mais");
                break;
        }
    }
}

I leave the link to those who are interested, it was a very clear explanation.

Using Switch Case for Ranges

The only change I had to make in the case of C# was to capture the entire division using the truncate method.

Math.Truncate Method

My code went like this:

         switch (Math.Truncate(average/2)){

          case 0: // 0 a 1                
            generalConcept = Concepts.E;
            break;

          case 1: // 2 a 3
            generalConcept = Concepts.D;                
            break;

          case 2: // 4 a 5
            generalConcept = Concepts.C;                
            break;

          case 3: // 6 a 7
            generalConcept = Concepts.B;                
            break;

          default: // 8 ou mais
            generalConcept = Concepts.A;                
            break;

        }

I hope I’ve helped!

Answer 2

Use if and else if thus:

int dias = 60;

if (dias < 30)
{
    System.Console.WriteLine("até 29");
}
else if (dias < 60)
{
    System.Console.WriteLine("de 30 até 59");
}
else if (dias < 90)
{
    System.Console.WriteLine("de 60 até 89");
}
else if (dias < 120)
{
    System.Console.WriteLine("de 90 até 119");
}
else
{
    System.Console.WriteLine("acima de 120");
}

Answer 3

There are several ways.

Switch

With switch That’s what comes to mind:

int mes = (int)System.Math.Floor((decimal)dias / 30);

switch(mes){
    case 0:
        break;
    case 1:
        // faz uma coisa
        break;
    case 2:
        // faz outra
        break;
    case 3:
    case 4:
        // faz outra..
        break;
    default:
        break;
}

Of course, it would have to be seen before whether the intervals are multiples of 30 and whether they are open or closed.

If

With If, the most obvious would be:

if (dias > 30){
    if (dias < 60){
        // faz uma coisa
    }
    else if (dias < 90){
        // faz uma outra coisa
    }
    [...]
}

or depending on whether it is a command:

var outputDeDias = EvalDias(dias);

private string EvalDias(int dias){
    if (dias < 30){
        return null;
    }
    if (dias < 60){
        return "uma coisa";
    }
    if (dias < 90){
        return "outra coisa";
    }
    [...]

    return null;
}   

Answer 4

Come on. If it’s "like this," we can write something like this.

  public void Tests(int diasInseridos)
    {
        int dias = diasInseridos;
        bool selected = false;//variavel que aciona um 'break' no momento em que entramos em alguma condição(if/else) válida
        int comparadorInicial = 30;//variavel comparadora de valor menor
        int comparadorFinal = 60;//variavel comparadora de valor maior

        while (selected == false)
        {
            if (dias == null || dias <= 0)
            {
                //Aqui retorna nenhum dia
                selected = true;//booleano para sair do laço
            }
            else if (dias > comparadorInicial && dias < comparadorFinal)
            {
                //Seu código retorna de acordo com os dias que seu programa detectou
                selected = true;//booleano para sair do laço
            }
            else
            {
                comparadorInicial = comparadorInicial + 30;
                comparadorFinal = comparadorFinal + 30;
            }

        }

    }

Answer 5

You must use several if's and not a switch. The switch serves to compare point values, not being able to compare intervals as you indicated in the question.

if (30 <= tempo && tempo < 60)
{
}
else if (60 <= tempo && tempo < 90)
{
}

There you go cuddling them if's us else'successively as far as you need.