Help with writing a function to check a users input

I am writing a script add reverb to an input file and have it so that the user can input the reverb time and amount of the direct sound they want mixed in. I've been trying to write a function to check the user input but have been having errors with the console getting stuck in the else statement no matter what input I have. This is the code for the function:

function ds = InputCheck(prompt1, prompt2)

instr = input(prompt1); % asks user for an input 
instr = str2double(instr);

while isnumeric(instr) == 1
    if (instr > 0) && (instr < 1) % limits for the input value
        ds = instr; % outputs the value
        break
    else
        instr = input(prompt2);
        instr = str2double(instr);
    end
end

And I have been calling it with this:

ds = InputCheck('Enter how much direct sound to mix in: ','Enter a number between 0 and 1: ');

This is what I get from the console:

>> ProcessingCombScript
Enter how much direct sound to mix in: 0.1
Enter a number between 0 and 1: 0.2
Enter a number between 0 and 1: 0.3
Enter a number between 0 and 1: 0.4
Enter a number between 0 and 1: 1
Enter a number between 0 and 1: 1.5
Enter a number between 0 and 1: -1

As you can see no matter what I enter I get the second prompt message. I know I've probably made a mess of this but any help and improvements would be greatly appreciated.

Answer 1

[Mark Sherstan]

You were on the right track. To make it easier on yourself you can include a string inside the input function like I did below. Also you want to use return instead of break once your solution is satisfied. Let me know if you need any clarification.

function ds = InputCheck()

x = input('Enter how much direct sound to mix in: ');

while 1
    if (x > 0) && (x < 1) % limits for the input value
        ds = x; % outputs the value
        return
    else
        x = input('Enter a number between 0 and 1: ');
    end
end

[Jakub Thurlow]

Thank you, I adapted it to keep the string inputs so that I can use it for the user inputting reverb time as well.

function ds = InputCheck(prompt1, prompt2)

x = input(prompt1);

while 1
    if (x > 0) && (x < 1) % limits for the input value
        ds = x; % outputs the value
        return
    else
        x = input(prompt2);
    end
end