Prog in C stating if x is divisible

Question

Good afternoon guys, all right?

I’m continuing my C exercises, and I got stuck in one more. Here is the statement of the same:

Write an algorithm that takes a keyboard number and tells you if it is divisible by 8, by 5, by 2 or if it is not divisible by any of these. Check for each of the numbers. Example: Number: 8 Divisible by 8 Divisible by 2

My code:

inicio

      escreva("Digite um número: ")
      leia(num)

      d2 <- (num%2)
      d5 <- (num%5)
      d8 <- (num%8)

      soma <- d2+d5+d8

      se (soma = 0) entao
         escreval("Número não é divisível por nenhuma das opções (2, 4 e 5)")
      senao
           se (d2 = 0) entao
              escreval("Número divisível por 2")
           senao
                se (d5 = 0) entao
                   escreval("Número divisível por 5")
                senao
                     se (d8 = 0) entao
                        escreval("Número divisível por 8")
                     fimse
                fimse
           fimse
      fimse

fimalgoritmo

Only, it only if I type "8" for example, it says it is divisible only by 2. And when I type 40, it said it is not divisible by any of the options.

Can someone help me with this?

Answer 1

There are two problems with this algorithm. The first problem is related to the first se:

se (soma = 0) entao

When the sum is zero, it means that it is divisible by all and not that it is not divisible by any.

The second problem is related to the entanglement of the if/senao. For example, when you say that:

se (d2 = 0) entao
    escreval("Número divisível por 2")
senao

This you are saying, enter this if, if anything happens, else do it. However, the se/senao should only be used when one condition influences the other, which is not the case in that situation. the fact that it is divisible by 2 does not make it divisible by 5 or 8, so these seshould not be nested.