looping back to an input

c = input ('what is the cement ratio you require?');

while c==0
    if c == 0;
      disp ('Enter a suitable amount');
      return  
else c == 0
    break         
end 
end  

%Looking to loop back to the input and repeat the question when 0 is inputted , however, when the code is ran it displays only the quote above and does not loop back to the input. I have probably made a silly mistake, but, I am hoping someone could maybe help.

Answer 1

[madhan ravi]

 c = input ('what is the cement ratio you require?'); % place this once again inside the if block after disp()

[Ciaran O'Connor]

Thank you very much !