Stop the iteration loop at desire Ea

I need help with my fixed point MATLAB coding. My iteration seems does not stop at my desired Ea. I want the iteration to stop at Ea<5 but the iteration will always stop at the max number of iteration, N. I have try to use the "break else return" but than it not show any of the iteration. Below are my MATLAB code:

function FixedPoint
clear
clc
cinitial = input('\nGive the initial value of c : ');  % Inputs initial value of x            
 iterations = 0; 
 N = 100;      % max no. iterations.
  
 
 fprintf('\n\nIteration       c           Ea(%)')
 
%-------------------- Runs Fixed Point algorithm --------------------------
 

    while iterations < N
     c = f(cinitial);  
     Ea = abs((c-cinitial)/c)*100;  % Calculates error.
     iterations = iterations + 1; % Calculates iteration no.
     cinitial = c;                % Replaces old value with new one.    
    
     
     if abs((c-cinitial)/c)*100 <= 5
         fprintf('\n%5.0f%16.8f   %f', iterations,c,Ea )
         
     end
     
 
     
     if iterations > 1000
         Ea <= 5;
         disp('No Convergence (Ignore answer below)')  % Halts algorithm after 10000 
     end                                               % iterations if convergence is
     end                                                 % not achieved.              
fprintf('\nSolution is %f \n', double(c)) 
end                                                 

%-------------------- Ends algorithm --------------------------------------
 

function F = f(c)
F = ((9.81 * 82).* (1-exp(-0.04878.*c)))/36;  % defines function 
end

%-------------------- End of program --------------------------------------

Answer 1

[Alan Stevens]

Like so

%cinitial = input('\nGive the initial value of c : ');  % Inputs initial value of x
cinitial = 1;
 iterations = 0; 
 N = 100;      % max no. iterations. 
               % This will need to be much larger if you tighten
               % the convergence tolerance 
 Ea = 1; 
 
 fprintf('\n\nIteration       c           Ea(%)')
 
%-------------------- Runs Fixed Point algorithm --------------------------
 

    while iterations < N && Ea > 10^-2   % You need an error test
     c = f(cinitial);  
     Ea = abs((c-cinitial)/c)*100;  % Calculates error.
     iterations = iterations + 1; % Calculates iteration no.
 
     if Ea <= 5
         fprintf('\n%5.0f%16.8f   %f', iterations,c,Ea )
         
     end
     cinitial = c;                % Replaces old value with new one.
                               
      
     if iterations > N   
         Ea <= 5;
         disp('No Convergence (Ignore answer below)')  % Halts algorithm after N 
     end                                               % iterations if convergence is
     end                                                 % not achieved.              
fprintf('\nSolution is %f \n', double(c)) 
                                                 

%-------------------- Ends algorithm --------------------------------------
 

function F = f(c)
F = ((9.81 * 82).* (1-exp(-0.04878.*c)))/36;  % defines function 
end

%-------------------- End of program --------------------------------------

Answer 2

[Mathieu NOE]

hello

I believe it is working better now

I tested it even with much tighter error constraint (down to 0.1)

I'll let you check

all the best

clear
clc
c_initial = input('\nGive the initial value of c : ');  % Inputs initial value of x            
 iterations = 0; 
 N = 1000;      % max no. iterations.
  
 
 fprintf('\n\nIteration       c           Ea(%)')
 
%-------------------- Runs Fixed Point algorithm --------------------------
 c_old = c_initial;
 
    while iterations < N
     c = f(c_old);  
     Ea = abs((c-c_old)/c)*100;  % Calculates error.
     iterations = iterations + 1; % Calculates iteration no.
     c_old = c;                % Replaces old value with new one.    
    
     
     if Ea <= 0.1
         fprintf('\n%5.0f%16.8f   %f', iterations,c,Ea )
         return
     end
     
     if iterations > 1000
         Ea <= 5;
         disp('No Convergence (Ignore answer below)')  % Halts algorithm after 10000 
     end                                               % iterations if convergence is
end                                                 % not achieved.              
fprintf('\nSolution is %f \n', double(c)) 
% end                                                 
%-------------------- Ends algorithm --------------------------------------
 
function F = f(c)
F = ((9.81 * 82).* (1-exp(-0.04878.*c)))/36;  % defines function 
end