About While Loops problems
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Is there anyway to end the program by entering "quit"? As the program keeps going despite displays "Exiting..."
The following is the syntax.
function Individual_Project_Final()
disp('Welcome to Unit Converter interface! ');
disp(' ');
while true
% Accept user input
input_str = input('Enter a number to be converted (or type "quit" to exit program): ', 's');
% Check if the user wants to quit
if strcmp(input_str, 'quit')
disp('Exiting...')
break;
end
% Convert input string to a number
numin = str2double(input_str);
% Check if the input is a valid number
if isnan(numin)
disp('Input invalid. Please enter a whole or decimal number (or type "quit to exit program): ');
else
disp('Input valid. Now please select the unit conversion type (or type "quit to exit program): ');
break;
end
end
% Display the menu for selecting conversion type
disp(' ')
disp('Select conversion type:')
disp('1) Celsius to Fahrenheit')
disp('2) Fahrenheit to Celsius')
disp('3) Centimeters to Inches')
disp('4) Inches to Centimeters')
disp('5) Meters to Foot')
disp('6) Foot to Meters')
disp('7) Kilometers to Miles')
disp('8) Miles to Kilometers')
disp('9) Grams to Ounces')
disp('10) Ounces to Grams')
disp('11) Kilograms to Pounds')
disp('12) Pounds to Kilograms')
disp('13) Tonnes to Tons')
disp('14) Tons to Tonnes')
while true
% Accept user input
input_str = input('Please select conversion type (1-14) (or type "quit" to exit): ', 's');
% Check if the user wants to quit
if strcmp(input_str, 'quit')
disp('Exiting...');
break;
end
% Convert input string to a number
convtype = str2double(input_str);
% Check if input is a valid conversion type
if ~ismember(convtype, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14])
disp('Conversion type invalid. Please enter a number from 1 to 14 (or type "quit to exit program): ');
else
disp('Input valid. We are now finalizing the resluts based on your input. ');
break;
end
end
% Call the user-defined function from Module 2
[numout,unit] = MyUnitConverter(numin,convtype);
% Output generation
disp(' ');
fprintf('The converted number is: %.2f %s\n', numout, unit);
end
3 个评论
VBBV
2024-5-19
If you want to quit entire program, type quit again in command window
VBBV
2024-5-20
@Stephen23 yes, return would be more suitable than quit or break
回答（1 个）
VBBV
2024-5-19
0 个投票
It has already exited, the first while loop, but it's waiting for next input from user ... See the message at bottom left of window in workspace, you need to select or provide a number
9 个评论
CHUN HIN KYLE
2024-5-19
CHUN HIN KYLE
2024-5-19
VBBV
2024-5-19
@CHUN HIN KYLE you need to put the end keyword at the end of function i.e. one line ahead of function end (see below) . Since there are multiple while loops inside your function, the program instructions (if any) still get executed after exiting the first while loop. So to exit the program using only one quit, putting the end keyword at the end will force the break statement to exit the entire while loop.
>> Individual_Project_Final % call the function from command window
function Individual_Project_Final()
disp('Welcome to Unit Converter interface! ');
disp(' ');
while true
% Accept user input
input_str = input('Enter a number to be converted (or type "quit" to exit program): ', 's');
% Check if the user wants to quit
if strcmp(input_str, 'quit')
disp('Exiting...')
break;
end
% Convert input string to a number
numin = str2double(input_str);
% Check if the input is a valid number
if isnan(numin)
disp('Input invalid. Please enter a whole or decimal number (or type "quit to exit program): ');
else
disp('Input valid. Now please select the unit conversion type (or type "quit to exit program): ');
break;
end
% Display the menu for selecting conversion type
disp(' ')
disp('Select conversion type:')
disp('1) Celsius to Fahrenheit')
disp('2) Fahrenheit to Celsius')
disp('3) Centimeters to Inches')
disp('4) Inches to Centimeters')
disp('5) Meters to Foot')
disp('6) Foot to Meters')
disp('7) Kilometers to Miles')
disp('8) Miles to Kilometers')
disp('9) Grams to Ounces')
disp('10) Ounces to Grams')
disp('11) Kilograms to Pounds')
disp('12) Pounds to Kilograms')
disp('13) Tonnes to Tons')
disp('14) Tons to Tonnes')
while true
% Accept user input
input_str = input('Please select conversion type (1-14) (or type "quit" to exit): ', 's');
% Check if the user wants to quit
if strcmp(input_str, 'quit')
disp('Exiting...');
break;
end
% Convert input string to a number
convtype = str2double(input_str);
% Check if input is a valid conversion type
if ~ismember(convtype, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14])
disp('Conversion type invalid. Please enter a number from 1 to 14 (or type "quit to exit program): ');
else
disp('Input valid. We are now finalizing the resluts based on your input. ');
break;
end
end
%
% Call the user-defined function from Module 2
[numout,unit] = MyUnitConverter(numin,convtype);
% Output generation
disp(' ');
fprintf('The converted number is: %.2f %s\n', numout, unit);
%>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
end % put the end of the first while before the end of function
end
CHUN HIN KYLE
2024-5-20
编辑：CHUN HIN KYLE
2024-5-20
Thanks, it worked!
Also, how am I gonna keep this program going in this case?
@CHUN HIN KYLE, if the user wants to continue further, you can modify the program as shown below
>> Individual_Project_Final % call the function from command window
function Individual_Project_Final()
disp('Welcome to Unit Converter interface! ');
disp(' ');
while true
% Accept user input
input_str = input('Enter a number to be converted (or type "quit" to exit program): ', 's');
% Check if the user wants to quit
if strcmp(input_str, 'quit')
disp('Exiting...')
break;
end
% Convert input string to a number
numin = str2double(input_str);
% Check if the input is a valid number
if isnan(numin)
disp('Input invalid. Please enter a whole or decimal number (or type "quit to exit program): ');
else
disp('Input valid. Now please select the unit conversion type (or type "quit to exit program): ');
% break; This break statement will stop program even when input is
% valid
end
% Display the menu for selecting conversion type
disp(' ')
disp('Select conversion type:')
disp('1) Celsius to Fahrenheit')
disp('2) Fahrenheit to Celsius')
disp('3) Centimeters to Inches')
disp('4) Inches to Centimeters')
disp('5) Meters to Foot')
disp('6) Foot to Meters')
disp('7) Kilometers to Miles')
disp('8) Miles to Kilometers')
disp('9) Grams to Ounces')
disp('10) Ounces to Grams')
disp('11) Kilograms to Pounds')
disp('12) Pounds to Kilograms')
disp('13) Tonnes to Tons')
disp('14) Tons to Tonnes')
%while true
% Accept user input
% input_str = input('Please select conversion type (1-14) (or type "quit" to exit): ', 's');
% Check if the user wants to quit
%if strcmp(input_str, 'quit')
% disp('Exiting...');
% break;
% end
% Convert input string to a number
convtype = str2double(input_str);
% Check if input is a valid conversion type
if ~ismember(convtype, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14])
disp('Conversion type invalid. Please enter a number from 1 to 14 (or type "quit to exit program): ');
else
disp('Input valid. We are now finalizing the resluts based on your input. ');
%break;
end
% end
% Call the user-defined function from Module 2
%>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
% The user defined function also has a display list of unit conversion
% categories as mentioned in my answer to one of your previous questions
% Its best to avoid redundant display of user query options both inside the
% my unit converter program as well as in this program. You can take choice
% which one to delete the redundant display of user query options.
%>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
[numout,unit] = MyUnitConverter(numin,convtype);
% Output generation
disp(' ');
fprintf('The converted number is: %.2f %s\n', numout, unit);
% add a line of code which asks user to continue further
c = input('Do you want to continue further ?:Type "Yes" (or type quit to exit):','s')
if strcmp(c,'Yes')
disp(' ')
elseif strcmp(c,'quit')
break;
end
%>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
end % put the end of the first while before the end of function
end
VBBV
2024-5-20
You could try using continue statement in the else part of code when the user enters inputs that are valid.
CHUN HIN KYLE
2024-5-20
Sorry, the loop just repeated itself instead of moving down after replacing "break" with "continue" after else part of code when the user enters inputs that are valid.
VBBV
2024-5-20
Try using the code which i modified (that has only one while loop , inner while loop is commented )
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2024-5-19
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