How do i create a loop for this expression?

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Burners
Burners on 1 Oct 2012
Answered: Nipun on 5 Jul 2022
Taking the number of iterations to be 5
By using i=1:5
How do i use a loop "for" command to express this?
1 x 8 + 1
12 x 8 + 2
123 x 8 + 3
1234 x 8 + 4
12345 x 8 + 5
  2 Comments
Jan
Jan on 2 Oct 2012
Edited: Jan on 2 Oct 2012
Is this a homework assignment? Do you think you can deliver the soultion without cheating, if it has been posted here? What will you teacher think, when she reads her question here?
Please post what you have tried so far and explain which problems occurred.
@Forum members: Please think twice before answering homework questions. Give the pupils and students a chance to learn. The reputation of this forum suffers from homework cheating.
Imogen Loveday
Imogen Loveday on 11 Mar 2015
pseudocode:
a = 0; for i = 1:5: a = 10a + i; f = 8a + i; print f;

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Answers (5)

Jan
Jan on 2 Oct 2012
There is an elegant way without using strings: In the first iteratation the multiplicator is 1. In the 2nd iteration it is 10*1 + 2. In the 3rd it is 10*(10*1 + 2) + 3. This can be exploited by using a temporary variable and modify it in each iteration.

Wayne King
Wayne King on 1 Oct 2012
Edited: Wayne King on 1 Oct 2012
One way:
kk = '';
for ii = 1:5
kk = [kk num2str(ii)];
out = str2num(kk)*8+ii
end
Of course if you want to store the output in an array
kk = '';
for ii = 1:5
kk = [kk num2str(ii)];
out(ii) = str2num(kk)*8+ii;
end
Now out is a 1x5 vector with the output values

Azzi Abdelmalek
Azzi Abdelmalek on 1 Oct 2012
Edited: Azzi Abdelmalek on 1 Oct 2012
s='12345'
for k=1:length(s)
res(k)=str2num(s(1:k))*8+k
end
or without a loop
s='12345'
out=arrayfun(@(x) 8*str2num(s(1:x))+x,1:5)

Maneet Kaur Bagga
Maneet Kaur Bagga on 5 Jul 2022
As per my understanding you want to use for loop for 5 iterations and display the result of the expression.
You can use a variable i with initial value 1 and a variable num with initial value 0
At every iteration the value of num will be (num*10 + i) and result will be (num*8 + i) and then you can print the result. You can refer the below code. Hope it helps.
num=0
num = 0
for(i=1:5)
num = num*10 + i
result = (num)*8 + i
end
num = 1
result = 9
num = 12
result = 98
num = 123
result = 987
num = 1234
result = 9876
num = 12345
result = 98765

Nipun
Nipun on 5 Jul 2022
Hi Burners,
Hope this works for you!
str = "0";
for i = 1:5
str = string(str2double(str)*10+(i));
ans = (str2double(str))*8+i
end

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