V = [7 9 -8 9 3 -8 -5 1 10 10 0 -7]; Write a script file that will determine how many times the values increase in V when going from one entry to the next.

Write a script file that will determine how many times the values increase in V when going from one entry to the next. For example, when going from V(1) to V(2) the values increase from 7 to 9 so this would be counted as an increase. The script should also count how many times the values decrease and how many times they do not change. I submitted the assignment without answering this question. I used the little MatLab knowledge I have, but could not figure out how to answer this particular question. The teacher's instructions were to not use the sum, min, nor max functions for the assignment. I was able to do it for finding the sum of the negatives and positives, displaying the minimum and maximum numbers, and prompting a user to enter a value to check for inequalities against V. I apologize if my questioning came of as rude and impolite. I just want to understand MatLab better.

clear; clc;

V = [7 9 -8 9 3 -8 -5 1 10 10 0 -7];

count = 0;

counts = 0;

counte = 0;

for k = 1:length(V)

    if V(1:k-1)> V(2:k)

        count = count + 1;

    end

    if V(1:k-1)< V(2:k)
        counts = counts + 1;

    end

    if V(1:k-1) == V(2:k)

        counte = counte + 1;

    end

end

fprintf( 'The number of times an increase occurs within the vector: %i \n',count);

fprintf( 'The number of times an decrease occurs within the vector: %i \n',counts);

fprintf( 'The number of times no change occurs within the vector: %i \n',counte);

[Stephen23]

@Josua Mensah: what exactly is your question? You think that if you copy your homework here then other people will do it for you? Do the people who do your homework get the course credits too?

Did you put in any effort into thinking about how to solve this simple task? Did you search for any similar threads on this forum to give you ideas about what operators you might use?

[Adam]

What about it? I'm fairly sure I don't need a script file that does that so why would I want to write one?

https://uk.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Josua Mensah]

I submitted the assignment without answering this question. I used the little MatLab knowledge I have, but could not figure out how to answer this particular question. The teacher's instructions were to not use the sum, min, nor max functions for the assignment. I was able to do it for finding the sum of the negatives and positives, displaying the minimum and maximum numbers, and prompting a user to enter a value to check for inequalities against V. I apologize if my questioning came of as rude and impolite. I just want to understand MatLab better.

[Adam]

The best way to understand Matlab is to just try things and come here with an attempt (even if it totally fails. We never mind someone who tries, shows their code, and fails, we mind those who appear not to have tried at all!) that at least shows your working and thought process at what to do.

I can never really understand assignments that tell you not to use certain functions. I suppose they have a purpose in learning, though the whole point of a package like Matlab is its massive library of built in functions!

I would assume your teacher wishes you to use a for loop to run over the values and do simple comparisons, storing your results as necessary.

[Jan]

@Joshua: Thanks for your explanations. Unfortuantely we have too many questions about homework from users who do not care about questions for clarifications. We do not want to support cheating also. But specific questions about Matlab are welcome.

Did you try anything? Then please post it, even if it fails.

[Jan]

@Joshua: +1, Well done. You kave asked a clear question and have solved the problem by your own with the assistance of the forum. This was not a "do-it-4-me" question. Please do not take it personally, that many users of the forum (like me) are spiky when homework questions are asked. When the authors show their own effort, questions are welcome - to be exact: they are the purpose of this forum :-)

Answer 1

[Jan]

V = [7 9 -8 9 3 -8 -5 1 10 10 0 -7];

To determine hwo many time the values goes up or down, you need two counters:

goesUp   = 0;
goesDown = 0;

Now you have to step through the elements and compare the current element with the previous one. This cannot work for the first element, so start with the 2nd:

for k = 2:length(V)
  disp(V(k))
end

Comparing with the previous element works like: V(k) < V(k - 1)

Now you can insert two IF commands using the corresponding conditions and increase the value of the concerned counter.

Instead of the IF command, you can use the fact, that the logical comparison replies TRUE and FALSE, which is converted to 1 or 0 automatically in arithmetic expressions:

x = 0;
x = x + (10 > 9)
x = x + (10 > 12)

Now try it and post your code in case of troubles.

Answer 2

[Josua Mensah]

clear; clc;
V = [7  9  -8  9  3  -8  -5  1  10  10  0  -7];
count = 0;
counts = 0;
counte = 0;
for k = 2:length(V)
  if V(k) > V(k-1)
      count = count + 1;
  end
  if V(k) < V(k-1)
      counts = counts + 1;
  end
  if V(k) == V(k-1)
      counte = counte + 1;
  end
end
fprintf('The number of times an increase occurs within the vector: %i \n',count);
fprintf('The number of times an decrease occurs within the vector: %i \n',counts);
fprintf('The number of times no change occurs within the vector: %i \n',counte);

[JS, code formatted]

Answer 3

[Rik]

We are not paid consultants, so don't give orders. This is the place where you can find help if you get stuck, not the place where you can find people that will do your homework for you.

However, I'm a sucker, so here are two lines of code that should help you.

a=sum(diff(v)==0);
b=sum(diff(v)>0);

[Josua Mensah]

I submitted the assignment without answering this question. I used the little MatLab knowledge I have, but could not figure out how to answer this particular question. The teacher's instructions were to not use the sum, min, nor max functions for the assignment. I was able to do it for finding the sum of the negatives and positives, displaying the minimum and maximum numbers, and prompting a user to enter a value to check for inequalities against V. I apologize if my questioning came of as rude and impolite. I just want to understand MatLab better.