How can I end a for-loop when a condition is met?

Hey,

I need to write a piece of code that asks the user to input a value for a temperature in degrees Celsius in the command window (number + ‘enter’) and computes the equivalent temperature in degrees Fahrenheit. For that I used the formula tfahr = 9/5 x tcels + 32. The script should keep running until the user presses the keys q + ‘enter’ in the command window.

This is what I have so far. However, the code is stopping after I entered a number but the program is supposed to keep running. Also, how do I implement that the program ends when I enter 'q'?

for value_celcius = input('Enter temperature in Celsius: ');
   if isnumeric(value_celcius)
       tfahr = 9/5 * value_celcius + 32;
       disp(tfahr)
   end
    disp('End of program. Goodbye!')
end

Thanks for the help!

Answer 1

[Walter Roberson]

while true
   value_str = input('Enter temperature in Celsius: ', 's');
   value_celcius = str2double(value_str);
   if isnan(value_celcius)
       break;
   end
   tfahr = 9/5 * value_celcius + 32;
   disp(tfahr)
end
disp('End of program. Goodbye!')

You input in string mode in case the user enters non-numeric. You convert the string to double. If the user entered something that is not a valid scalar double, then str2double() returns nan.

[jian wu]

bingo

Answer 2

[Cris LaPierre]

Look into using a while loop instead of a for loop.

[Ari Hauser]

Alright, I used a while loop instead, thanks! However, wow can I end the program with the input 'q'?

[Cris LaPierre]

value_str = 'a';
while ~strcmpi(value_str,'q')
   value_str = input('Enter temperature in Celsius: ', 's');
   ...