Having trouble with while loops problem

I'm required to write a program what will accept positive numbers, and calculate both the average of them and the geometric mean(nth root of (x1*x2*x3...*xn). While loops are to be used to get the input numbers, and terminate the inputs that are negative. While loops in general confuse me so can you please tell me what i did wrong.

ttotal=0;

total=0;

cnt=0;

x=1;

y=1;

while x>=0

    x=input('Please enter a positive number:');
    cnt=cnt+1;
    total=(total+x)/cnt;
    if x<0
        break;
    end
while y>=0
    y=input('Please enter a positive number:');
    cnt=cnt+1;
    ttotal=(ttotal*y)^(cnt/2);
    if y<0 
        break;
    end
    fprintf('The geometric mean is %g',ttotal)
    fprintf('The average of the inputed numbers is %g',total)
end
end
fprint('Program-Terminated')

[Paulo Silva]

instead of while x>=0 and y>=0 use while 1

put if x<0,break,end after the user input x and

if y<0,break,end after the user input y

Follow Andrew tips and you should be fine.

Answer 1

[Andrew Newell]

Here are some things that are wrong:

1. You're entering separate numbers x,y for the arithmetic and geometric means (you should be using x for both).
2. Initially ttotal is zero, so every time you multiply it by something you get zero (try 1).
3. If x<0, break, end is redundant (it's going to exit anyway at the top of the loop).
4. You should save division by cnt to the end (otherwise you're dividing by 1, 2, 3, etc.). Ditto for the power of cnt/2.

[John]

Thanks! that fixed it, how do i get is to accept say 4 inputs and then calculate the average and geometric mean.

revised version:

ttotal=1;

total=0;

cnt=0;

while x>=0

x=input('Please enter a positive number:');

cnt=cnt+1;

total=total+x;

ttotal=(ttotal*y);

fprintf('The geometric mean is %g',ttotal^(cnt/2))

fprintf('The average of the inputed numbers is %g',total/cnt)

end

fprintf('Program-Terminated')

[Andrew Newell]

You're getting closer, but you haven't done point 4 yet (by end I mean *after* the loop). Also, think about when you should ask for a number. What happens when you enter a negative number? Finally, you might want to check your definition of a geometric mean.