Convert for loop to while loop

Hi!

I am trying to convert a for loop to a while loop that will produce the same result. Although I understand the concept, I keep running into an error that I'm not sure how to fix. Any help would be appreciated!

The for loop:

x=0;

y=randi(100,1,5);

for i = 1:5 x=x+y(i);

end disp(x);

And I came up with the while loop:

x=0;
y=randi(100,1,5);
i=1;
while i <= 5
 i=i+1;
 x=x+y(i);
end
disp(x);

However, it keeps giving me the error "Index exceeds the number of array elements (5).

Error in Example (line 6)

x=x+y(i);"

I don't understand why this is happening, since the while loop should run 5 times, increasing the i value by 1 each time, and the vector y has 5 elements.

Like I said, any help would be appreciated! Thank you!

Answer 1

[madhan ravi]

Initialise ii with 0 instead of 1. Otherwise you start it as 2 therefore when you reach 5 it gets incremented to 6 exceeding the number of elements in y which has 5 elements.

[madhan ravi]

 y = randi(100, 1, 5);
 x = zeros(size(y)); % preallocate x properly 
 ii = 0;
 while ii <= 5
       ii = ii + 1;
       x(ii) = x(ii) + y(ii);
 end
 x