More than 1 elseif statement with 3 different numbers

I've been trying to figure this out without 2 separate if statements. Bunch of googling,etc... And still can't find an applicable answer

totalSales=input('Enter the total sales number of the employee ');
if totalSales < 5000 % less than 5000 total sales
  additionalBonus = 0;
elseif totalSales < 10000 >= 5000 % less than 10000, but equal or greater than 5000 total sales
  additionalBonus = totalSales * 0.03;
elseif totalSales >= 10000 % greater than or equal to 10000 total sales
  additionalBonus = totalSales * 0.06;
end

I'm doing an example from a book, and I'm having trouble with the code recognizing the third statement.

If I write >= 10000 as a separate if statement, it works fine, but if I try if,elseif,else, it doesn't work.

6500 total sales for example, uses 0.06 instead of 0.03 function.

Do I have to use a separate if statement for the third function?

Here's the full code:

baseSalary=input('Enter the base salary of the employee ');

noOfServiceYears=input('Enter the number of service years for the employee ');
if (noOfServiceYears <= 5)
     bonus = 10 * noOfServiceYears;
elseif (noOfServiceYears > 5)
    bonus = 20 * noOfServiceYears;
end

totalSales=input('Enter the total sales number of the employee ');
if totalSales < 5000 % less than 5000 total sales
  additionalBonus = 0;
elseif totalSales < 10000 >= 5000 % less than 10000, but equal or greater than 5000 total sales
  additionalBonus = totalSales * 0.03;
elseif totalSales >= 10000 % greater than or equal to 10000 total sales
  additionalBonus = totalSales * 0.06;
end

payCheck = baseSalary + bonus + additionalBonus;

[John D'Errico]

No. You did NOT figure it out. Read the answer by Stephen.

X < A < Y

does not do what you think it does. Yes, it is a common shorthand in mathematics, but not in MATLAB.

[Rik]

Question restored from Google cache. An archive was also created here.

Answer 1

[Stephen23]

You should have been a bit more patient answering and accepting your own question, because your "answer" is totally wrong. The code that you think works is actually doing something quite different to what you imagine. Lets have a look at what it really does...

The basic problem is that you are performing two logical relations simultaneously: MATLAB only supports one logical relational operation at once. In summary:

X<A<Y     % is NOT valid for comparing A against X and Y
X<A & A<Y % This compares A with both X and Y

In MATLAB logical relational operators follow the standard rules of operator precedence. Look at this example carefully:

>> 3<4<2
ans =
     1

The output is true, so does this mean that 4<2 ? Of course not, we just have to remember the operator precedence rules, just like in high school. This is evaluated according to those rules as:

>> (3<4)<2
ans =
     1

where

>> 3<4
ans =
     1

So 3<4<2 is actually equivalent to 1<2, which is of course very true:

>> 1<2
ans =
      1

Now lets have a look at your answer. Whatever values you have for totalSales the answer is going to be true:

>> totalSales = 0;
>> totalSales >= 5000 < 10000
ans =
     1
>> totalSales = 7500;
>> totalSales >= 5000 < 10000
ans =
     1
>> totalSales = 20000;
>> totalSales >= 5000 < 10000
ans =
     1

Can you see why? Because of operator precedence, it is actually equivalent to this:

(totalSales >= 5000) < 10000

Note that it does not matter if the first comparison totalSales >= 5000 produces a 0 or a 1 output, because both of 0 and 1 are less than 10000, so the answer is always going to be true.

The real solution for your original question was something like this:

totalSales = input('Enter the total sales number of the employee ');
if totalSales<5000
    additionalBonus = 0;
elseif totalSales<10000
    additionalBonus = totalSales * (0.03);
else
    additionalBonus = totalSales * (0.06);
end

The comparisons totalSales >= 5000 and totalSales >= 10000 are totally superfluous, so I removed them. Obviously the value must be greater than 5000, because if it wasn't it would be caught by the first if comparison, ditto the greater than 10000.

[John D'Errico]

I deleted the self-accepted answer from the OP since it was clearly wrong. Rather than other novices seeing that answer and thinking that it made sense, it had to be deleted.

[Julian Perge]

I decided to come back after 6 years to comment on this and say I will never accept this answer. The amount of aggression from your comments John, is ridiculous.

On top of that, I had zero desire to continue working with Matlab after posting this due to the hostility and backhanded responses received from me posting this question from both you John, and Stephen.

What's the point of asking for help if the answer is going to be done is a contrived, holier than thou way that makes newbies such as myself feel inadequate to even bother moving forward to try and understand matlab. I'm not surprised that these 2 responses were almost identical to how a mod on Stack Overflow would respond.

Pathetic.

[Adam Danz]

@Julian Perge, sorry you had a negative experience in the forum. I don't speak for any of the other contributors nor for MathWorks but I can relate to the frustration that ensues after investing time into answering a question only to see that a wrong answer was accepted instead. Despite being a 6 year old post, it currently has 55 views in the past 30 days. At this rate, that's 4015 views since it was posted. Since your wrong answer was apparently accepted, thereby drawing more attention to it, and since the incorrect solution appears to be a common pitfall for other newbies, I can see why it needed deemphasizing. It looks like Stephen invested a chunk of time to explain why your answer was wrong.

[Rik]

@Julian Perge How should this answer have been phrased? If your answer was incorrect, how should that have been worded? And if it wasn't, can you explain why this answer is incorrect? If you don't like the tone, can you explain what exactly should be rephrased in order for you to be able to accept this answer? You can also write up your own answer. Don't immediately accept it, so we have the opportunity to suggest any edits that might make it easier for novices to understand.

This is an important question, which is often asked, so it merits a thorough (and correct) answer.

I'm sorry you feel these responses were hostile. I'm confident this wasn't the intention of either Stephen or John. Remember that it is difficult to convey tone of voice in text, especially if not all participants are reading/writing in their native language.

I will be restoring the original question, as this thread clearly serves a purpose, as Adam also indicates.

[Jan]

@Julian Perge: In this forum we concentrate on solving Matlab problems. The contents of the forum is thought as database for Matlab users searching for help and solutions. Therefore editors and admins care about the correctness of answers.

Of course there can be cases, in which different opinions co-exists and there is no unique solution. Sometimes users do not agree and especially in such cases it is the goal of this forum to keep calm and polite. This helps to solve Matlab problems and to avoid flamewars and frustration.

I do not see aggressiv formulations or insults in the contributions of John and Stephen. Remember, that they are some foreign people from the internet, who spend their time an effort voluntarily to help others. They might have a different cultural background, so do not interprete to much emotions in their formulations. I recommend to select the parts of the answers, which solve the problem, to ignore the rest and not to take the statements personally.

You see, that members of this forum care about your flags. Let me mention the Community Guidelines:

Do not:

• 6. Chastise newcomers or insult other members
• 14. Edit posts to make them unreadable
• Respond to questions/comments if you feel your effort isn't well spent

Thank you for repsecting this.