Help on my function script?

My function is [s,m]=collatz(the input number) which I used x=input('Enter a natural number:'). If I want an even input to be divided by 2, and an odd input to be multiplied by 3 plus 1. This goes on as long as the number is greater than one. Ex: starting with 3 it would give 3-10-5-16-8-4-2-1. How would I set this up?

function[s,m]=collatz()
x=input('Enter a natural number:')
while mod(x,2)==0 %shows x(natural number) is even
x=x/2
if mod(x,2)==1 %shows x(natural number) is odd
x=x*3+1
end
end

Answer 1

[Fangjun Jiang]

almost there

while x>1
    if mod(x,2)==0 %shows x(natural number) is even
        x=x/2
    elseif mod(x,2)==1 %shows x(natural number) is odd
        x=x*3+1
    end
end

[Fangjun Jiang]

to prevent infinite loop when the input is a decimal number, for example 3.2, modify it as below

x=input('Enter a natural number:');
while x>1
    if mod(x,2)==0 %shows x(natural number) is even
        x=x/2
    elseif mod(x,2)==1 %shows x(natural number) is odd
        x=x*3+1
    else
        x
        break;
    end
end