how can I use a while loop for LCM?

I want to write a program that will allow me to add the value of 'x', and then if the sum is equal to the input for y stop and display that value as the LCM. But, if not, add y+y+y+y.... until x=y.

[Paridhi Yadav]

Can you explain clearly what you want ?

Answer 1

[Matt Dickson]

To do it iteratively as you laid out, you'd have something like

function [leastCommon] = lcm(a,b)
 a1 = a;
 b2 = b;  
 while a1 ~= b1
    if a1 > b1
       b1 = b1 + b;
    else
       a1 = a1 + a;
    end
 end
 leastCommon = a1;
end

I'm not sure if you're set on doing it the way you described, but a simpler way to find the LCM is to use the greatest common division (GCD). Say you want to know the LCM of two numbers, a and b. Then

LCM = (a * b) / gcd(a,b)

The GCD is easy to find via the Euclidean algorithm, which is recursively defined as

 function [ret] =  gcd(a, b)
    if b == 0
       ret = a; 
    else
       ret = gcd(b, mod(a, b));
    end