Mathematical and logical operators in Visualg

Why don't the highlighted codes in asterisk work the way I chose?

I realized that using the smaller number first and the larger number second, it works normally, but I was hunched over to know why it's wrong.

   algoritmo "semnome"
var
   nota1, nota2, media: real
inicio
      Escreval ("--------------------------")
      Escreval ("ESCOLA TIO PATINHO CRACUDO")
      Escreval ("--------------------------")
      Escreval ("Digite a primeira nota: ")
      Leia (nota1)
      Escreval ("Digite a segunda nota: ")
      Leia (nota2)
      media <- (nota1 + nota2) / 2
      Se **(media >=10) e (media <9)** entao
         Escreval ("Média: ",media)
         Escreval ("Aproveitamento: A")
      senao
           Se **(media >=9) e (media <8)** entao
              Escreval ("Média: ",media)
              Escreval ("Aproveitamento: B")
      senao
              Se **(media >=8) e (media <7)** entao
                 Escreval ("Média: ",media)
                 Escreval ("Aproveitamento C")
      senao
                 Se **(media >=7) e (media <6)** entao
                    Escreval ("Média: ",media)
                    Escreval ("Aproveitamento D")
      senao
                    Se **(media >=6) e (media <5)** entao
                       Escreval ("Média: ",media)
                       Escreval ("Aproveitamento E")
      senao
                          **Se (media <4) entao**
                          Escreval ("Média: ",media)
                          Escreval ("Aproveitamento F")
                                                 FimSe
                                        FimSe
                                FimSe
                          FimSe
                  FimSe
              FimSe
fimalgoritmo
Author: Maniero, 2020-03-25
Source

1 answers

Let's leave a little more Portuguese than it is:

If average is more than or equal to and average is less than 8.

So the two comparisons must be true for the whole expression to be true, this is the function of the relational operator e (which is usually and or && in real languages).

Let's say the number is greater than or equal to 9, so it's true. So that number can be 9, 10, 11, 12 or 13, or any other number in that number. sequence. But he can't be 8, or 7, or less than that, right?

Then, knowing this, he goes on the second comparison and we can already conclude that it will be false, correct?

If one is true and the other is false, How can the whole be true after applying the operator e? There's no way in any situation.

In your question is spoken:

Don't work the way I chose

It gets complicated until we talk about what is right because the question says you chose something, but only you know what was chosen. There is no clear definition of what he wished to do.

I've tried to infer what it should be, but it doesn't seem to have logic within the knowledge I have of grade classifications. The A should be only one note up, so I don't know why it compares to the 8. The B should start from a lower note and go to a slightly higher one, and so on. The code tries to consider B for a grade above 8 and below 7, it doesn't make sense.

Who knows wanted to do: 

Se media > 7 e media <= 8 entao

Shouldn't do so many indentations either, one level is enough, imagine if I had more comparisons, where would that code end up?

 1
Author: Maniero, 2020-03-26 10:30:52