how to compare previous and next values in MATLAB?

Write a function called number_pattern that takes no input arguments and returns no output arguments. Instead it gets it input via the function input. It asks for a number repeatedly until the user puts in the same number twice in a row. The loop that it uses must be a while-loop. Here is an example run:

>> matching_number

Please input a number: 4

Please input number (I'm looking for a pattern): 5

Sorry, that's not what I'm looking for.

Please input number (I'm looking for a pattern): 6

Sorry, that's not what I'm looking for.

Please input number (I'm looking for a pattern): 7

Sorry, that's not what I'm looking for.

Please input number (I'm looking for a pattern): 7

That's it. Well done!

The function should behave just as in the example, using exactly the same phrasing in its output (e.g., “That’s it. Well done!”)

I tried to write code but I did not understand how can I compare previous "b" and next "b". Here is my code..

[Turlough Hughes]

I would treat a as being the last value (inputted by the user) and b as the current value. Following user input, you can check if a == b and following that you need to update a for the next iteration so that it is equal to b from the current one.

[Mathieu NOE]

yeap

if you share you code, we can further help you

[zehra ülgen]

function number_patter

a = input ('Please input a number: ');

while 1

b = input ('Please input number (I''m looking for a pattern): ');

if a == b

fprintf('That''s it. Well done!\n');

return;

elseif b == b

fprintf('That''s it. Well done!\n');

return;

else

fprintf('Sorry, that''s not what I''m looking for.\n');

end

end

[zehra ülgen]

'number repeatedly until the user puts in the same number twice in a row'

to do that statement I should compare the previous 'b value' and new 'b value'. But when I said b == b my code is not working. How can I compare last two b value?

Answer 1

[Mathieu NOE]

hi

I believe this works :

function number_patter
b = [];
a = input ('Please input a number: ');

while 1
b = input ('Please input number (I''m looking for a pattern): ');
    if a == b
        fprintf('That''s it. Well done!\n');
        return;
    elseif b == prev_b
        fprintf('That''s it. Well done!\n');
        return;
    else
    fprintf('Sorry, that''s not what I''m looking for.\n');
    end 
    
prev_b = b;

end 

[zehra ülgen]

I'm sorry it's nor working..

>> number_pattern

Please input a number: 4

Please input number (I'm looking for a pattern): 5

Unrecognized function or variable 'prev_b'.

Error in number_pattern (line 9)

elseif b == prev_b

But if I change the prev_b = b; like that.. Code is working.. Thank you very much for your helps..

function number_patter
b = [];
a = input ('Please input a number: ');
while 1
prev_b = b;
b = input ('Please input number (I''m looking for a pattern): ');
    if a == b
        fprintf('That''s it. Well done!\n');
        return;
    elseif b == prev_b
        fprintf('That''s it. Well done!\n');
        return;
    else
    fprintf('Sorry, that''s not what I''m looking for.\n');
    end  
end 

[Mathieu NOE]

yes better this way ! :)

Answer 2

[Jon]

You need to create a new variable, call it for example prevB. After each loop set

prevB = B

when you do your comparison compare prevB and B

Note you will need to initialize prevB before entering the loop so it is defined the first time through. Just set it to something that the user would never enter for example prevB = inf

[zehra ülgen]

I'm not sure I got you right but I tried to do something and it is not working again..

function number_patter

a = input ('Please input a number: ');

prevB = input ('Please input number (I''m looking for a pattern): ');

while 1

b = input ('Please input number (I''m looking for a pattern): ');

if b == a

fprintf('That''s it. Well done!\n');

break;

elseif b == prevB

fprintf('That''s it. Well done!\n');

break;

else

fprintf('Sorry, that''s not what I''m looking for.\n');

end

end

[Jon]

You need to assign prevB = b insinde of the loop