FOR Loop

Let us say I have a row vector with "n" number of rows.

e.g. [0 27 29 45 66]';

How can I write a command using a FOR loop, that adds the first element with the second element, then the second element with the third element and so on until it gets to the "n" number of rows.

And in the end adding up all those answers.

So like: (0+27)+(27+29)+(29+45)... and so on.

I'm only a beginner in MatLab and spent hours trying to figure this out. Hope you guys can help. Thanks for the help in advance. :D

Answer 1

[Andrei Bobrov]

aout = 0;
for i1 = 1:numel(a)-1;
    aout = aout + a(i1) + a(i1+1);
end

without loop for..end

n = numel(a)
aout = sum(a(1:n-1)+a(2:n))

[Walter Roberson]

sum(a(1:n-1)+a(2:n)) can also be expressed as

a(1) + 2*sum(a(2:n-1)) + a(n)

[Mayu]

Is there a command to just display the last cumulative element.

when i try to display the "aout" it always comes out as the cumulative frequency throughout the whole array.

[Sean de Wolski]

aout(end)

Answer 2

[Shouvik Das]

Considering you need to store each intermediate output in another array. Let input array with n rows be inputArray

 outputArray=[];
 for i=1:length(inputArray)-1
 outputArray(i)=inputArray(i) + inputArray(i+1);
 end

Hope this helps.

Regards Shouvik

[Mayu]

Thanks, works wonderfully :D

Answer 3

[Anurag Pratap Singh]

Hi Mayu

You could use an extra array for storing every output let say addArr array and then add each elements of the addArr.

addArr = [];
for i = 1:length(inputArr)
    addArr(i) = inputArr(i)+inputArr(i+1);
end

Then add each element of addArr

result = 0;
for i = 1:length(addArr)
    result = result+addArr(i);
end

The result variable has the cummulative sum of all the elements in input array.

Thank you