How to plot multiple lines in the same graphics using GUI?

I was trying to plot a graphics of 'c vs X' for different 't'(t1,t2,t3 etc) in the same graph using GUI. Note that, lines for different t should be plotted one by one (i.e after plot of line 1 (t1), it will wait for input of t2 to plot line 2 and so on).Is there anybody to help in doing that? Thanks in advance !

MY CODE IS:

function varargout = gui_trail(varargin) 
% GUI_TRAIL MATLAB code for gui_trail.fig 
% GUI_TRAIL, by itself, creates a new GUI_TRAIL or raises the existing 
% singleton*. 
% 
% H = GUI_TRAIL returns the handle to a new GUI_TRAIL or the handle to 
% the existing singleton*. 
% 
% GUI_TRAIL('CALLBACK',hObject,eventData,handles,...) calls the local 
% function named CALLBACK in GUI_TRAIL.M with the given input arguments. 
% 
% GUI_TRAIL('Property','Value',...) creates a new GUI_TRAIL or raises the 
% existing singleton*. Starting from the left, property value pairs are 
% applied to the GUI before gui_trail_OpeningFcn gets called. An 
% unrecognized property name or invalid value makes property application 
% stop. All inputs are passed to gui_trail_OpeningFcn via varargin. 
% 
% *See GUI Options on GUIDE's Tools menu. Choose "GUI allows only one 
% instance to run (singleton)". 
% 
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help gui_trail

% Last Modified by GUIDE v2.5 08-Feb-2011 04:15:12

% Begin initialization code - DO NOT EDIT 
gui_Singleton = 1; 
gui_State = struct('gui_Name', mfilename, ... 
                   'gui_Singleton', gui_Singleton, ... 
                   'gui_OpeningFcn', @gui_trail_OpeningFcn, ... 
                   'gui_OutputFcn', @gui_trail_OutputFcn, ... 
                   'gui_LayoutFcn', [] , ... 
                   'gui_Callback', []); 
if nargin && ischar(varargin{1}) 
    gui_State.gui_Callback = str2func(varargin{1}); 
end

if nargout 
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:}); 
else 
    gui_mainfcn(gui_State, varargin{:}); 
end 
% End initialization code - DO NOT EDIT

% --- Executes just before gui_trail is made visible. 
function gui_trail_OpeningFcn(hObject, eventdata, handles, varargin) 
% This function has no output args, see OutputFcn. 
% hObject handle to figure 
% eventdata reserved - to be defined in a future version of MATLAB 
% handles structure with handles and user data (see GUIDATA) 
% varargin command line arguments to gui_trail (see VARARGIN)

% Choose default command line output for gui_trail 
handles.output = hObject;

% Update handles structure 
guidata(hObject, handles);

% UIWAIT makes gui_trail wait for user response (see UIRESUME) 
% uiwait(handles.figure1);

% --- Outputs from this function are returned to the command line. 
function varargout = gui_trail_OutputFcn(hObject, eventdata, handles) 
% varargout cell array for returning output args (see VARARGOUT); 
% hObject handle to figure 
% eventdata reserved - to be defined in a future version of MATLAB 
% handles structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure 
varargout{1} = handles.output;

function value_x_Callback(hObject, eventdata, handles) 
% hObject handle to value_x (see GCBO) 
% eventdata reserved - to be defined in a future version of MATLAB 
% handles structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of value_x as text 
% str2double(get(hObject,'String')) returns contents of value_x as a double

% --- Executes during object creation, after setting all properties. 
function value_x_CreateFcn(hObject, eventdata, handles) 
% hObject handle to value_x (see GCBO) 
% eventdata reserved - to be defined in a future version of MATLAB 
% handles empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows. 
% See ISPC and COMPUTER. 
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor')) 
    set(hObject,'BackgroundColor','white'); 
end

function value_t_Callback(hObject, eventdata, handles) 
% hObject handle to value_t (see GCBO) 
% eventdata reserved - to be defined in a future version of MATLAB 
% handles structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of value_t as text 
% str2double(get(hObject,'String')) returns contents of value_t as a double

% --- Executes during object creation, after setting all properties. 
function value_t_CreateFcn(hObject, eventdata, handles) 
% hObject handle to value_t (see GCBO) 
% eventdata reserved - to be defined in a future version of MATLAB 
% handles empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows. 
% See ISPC and COMPUTER. 
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor')) 
    set(hObject,'BackgroundColor','white'); 
end

% --- Executes on button press in draw. 
function draw_Callback(hObject, eventdata, handles) 
% hObject handle to draw (see GCBO) 
% eventdata reserved - to be defined in a future version of MATLAB 
% handles structure with handles and user data (see GUIDATA)

%%%CODE TO EXECUTE PUSH BUTTON %%%

another='Yes'; 
while strcmp(another,'Yes') 
x=str2double(get(handles.value_x,'String')); 
t=str2double(get(handles.value_t,'String')); 
x=1:x; 
c=t*exp(-0.05*x); 
figure; 
plot(x,c(x));

qstring1='Another calculation?'; 
another=questdlg(qstring1,'Another calculation?','Yes','No','No'); 
if strcmp(another,'Yes') 
qstring='Draw on same graph?'; 
dsameG=questdlg(qstring,'Draw on same graph?','Yes','No','No'); 
else 
dsameG='No'; 
end 
if strcmp(dsameG,'Yes') 
hold on; 
end 
end

N.B. Sorry for so long submission !

Answer 1

[Walter Roberson]

Your draw callback always creates a new figure and then plots in to that. You should instead do something like

ah = findobj(0,'Type','axes','Tag','MyPlotAxes');
if isempty(ah)
  fh = figure;
  ah = axes('Parent',fh, 'Tag', 'MyPlotAxes');
  hold(ah, 'on');
end

plot(ah, x, c(x));

[Bijit Banik]

@ Walter Roberson: Thank you very much.

[Bijit Banik]

Hello Mr. Roberson,

Need your help once agin. Could you please tell me how to solve that-below ?

I want to put different legend for each t (t1,t2 etc)with different color or may be shape (legends should be autometically generated).

Thanks in advance.

[Jan]

@Bijit: Please _accept_ Walter's answer, if it satisfies your question. And open a new thread for a new question. Thanks.