Using while loop to determine average

I need to calculate the average using a while loop only. The first step is to add up all my vectors into one number. This is what I've done so far.

fid = fopen('Watts.dat');
r1 = fscanf(fid,'%f');
stop = 0;
sumx = 0;
n = 1;
while (stop <= 31)
 f = r1(n)
 sumx = r1(f) + sumx;
 stop = stop +1;
 n = n+1
end

However, I get the message

Attempted to access r1(2005.6); index must be a positive integer or logical.

I can't round these numbers. Do you guys have any suggestions?

[Khalid Ghwani]

Use a while loop to write a Matlab program to find the average any set of numbers entered by the user (not of known size)

Answer 1

[Jan]

Replace

sumx = r1(f) + sumx;

by

sumx = f + sumx;

Note: You do not need two variables "n" and "stop". One of them is enough.

Do not forget to close opened files with fclose.

[student187]

Thank you for your time, however, don't I need the n to push matlab to find the next data point in the vector?