write an m-file using while loop which calculates the sum of elements within the following vector x=[5 2 -9 10 -1 9 -1] until a number greater than 8 is met? please help i have tried and i am confused on how to do this.

i have tried and my codes don't work, how can i do this with a while loop?

[the cyclist]

I assume this is a homework assignment. I suggest you post what you have tried and we can suggest where you went wrong.

[kelechi okegbe]

s=[5 2 -9 10 -1 9 -1]
n=0;
a=0;
for n=s(1):s(6)
while sum(s)<=8
a=a+n;
sum(s)=a
end
end
  % code
end

Answer 1

[Thorsten]

x=[5 2 -9 10 -1 9 -1];
partialsum = 0;
i = 1; 
while partialsum <= 8
  partialsum = partialsum + x(i);
  i = i + 1; 
end

[kelechi okegbe]

Perfect answer Thorsten, I was indeed summing the entire loop instead of summing incrementally. Thank you Thorsten and thanks to all, my problem is solved.

Answer 2

[Joseph Cheng]

general outline would be

x=[5 2 -9 10 -1 9 -1];
while currentsum<=8
  currentsum = %what you want to sum up.
end

[kelechi okegbe]

Thank you for your answer. When i run it, it just sums up the entire vector. It is supposed to stop summing at 5+2+(-9)+10+(-1)+9=16.

x=[5 2 -9 10 -1 9 -1];
while currentsum<=8
 currentsum= sum(x)
end
  % code
It returns 15 instead of 16.

[Walter Roberson]

"%what you want to sum up." should only be a subset of x, not all of x. Your loop should be incrementing the index of the last element that you are paying attention to. sum(x(1:SomeIndex)) and keep increasing SomeIndex. Make sure you stop when you reach the end of the array.