How can I fix this Infinite While loop?

I've writtent the code below to calculate interest I know it's not going to calculate it the way that it's written. My question to the community is why this code creates an infinite loop???

I've ran the code in blocks and have noticed that for some reason the value of b becomes infity as the code continues to run past the line where b is recalculated (b = b-p % New Principele value ). Could someone please take a look at this and let me know what I may be doing wrong.

a  = 12
b = 13000
x = .2004/12 % Interest
p = 700 
count = 0
i = 1

  while b >= 0
        
        I = b*x % Interest Payment 
        p = p-I % Amount taken of principal
        
        b = b-p % New Principele value  
        
        k = b/p % Increasing I while b>= is true
      
        if b == 0
            break
        end
    end

Answer 1

[David Hill]

a  = 12;
b = 13000;
x = .2004/a % Interest
payment = 700;%I assume you want a constant payment until the last payment
count=1;
  while b > 0
        
        I(count) = round(b*x,2) % Interest Payment 
        p = payment-I(count) % principal reduction
        
        b(count+1) = b(count)-p % New Principele value  
        count=count+1;
    end

[Daniel Casas]

I appreciate the help, and effort but I'd like to know if you ran the code and ran into the same problem I had?

[Daniel Casas]

I got the code running the way that I wanted thank to your code, it helped me realize what I was doing wrong thanks. It's still not finished but here is the working While loop.

clear all
% Interest Payment
a  = 12;
b = 13000;
x = .1304/a % Interest
payment = 700;%I assume you want a constant payment until the last payment
count=1;
I = []
c = []
  while b > 0
        c(1) = b
        I(count) = b*x % Interest Payment 
        p = payment-I(count) % principal reduction
        count=count+1;
        
        c(count) = c(count-1)-p % New Principele value  
        b =c(count) 
    end