while loop error with conditional statment

i %ignore this i code starts from below 
interval = 1.2
x_int = 0:intereval:c
i=1
while x_int(i) <= c
      ya(i) = ((5*c)*(TT/100))*((0.2969*sqrt(x_int(i)/c))-(0.126*(x_int(i)/c))-...
          (0.3516*(x_int(i)/c)^2)+(0.2843*(x_int(i)/c)^3)-(0.1015*(x_int(i)/c)^4));
      yb(i)= -((5*c)*(TT/100))*((0.2969*sqrt(x_int(i)/c))-(0.126*(x_int(i)/c))-...
          (0.3516*(x_int(i)/c)^2)+(0.2843*(x_int(i)/c)^3)-(0.1015*(x_int(i)/c)^4));
   i=i+1
end

Here c can be any whole number (assuming it's bigger than its interval). when i run this i get an error saying Index exceeds matrix dimensions. at while x_int(i) <= c Please help!

Answer 1

[Basil C.]

OR you could just modify your WHILE loop condition as :

 while (x_int(i) <= c && i<length(x_int))