how to assign zero to a vaiable

Question

Imaad Aslam 2023-1-28

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https://ww2.mathworks.cn/matlabcentral/answers/1902160-how-to-assign-zero-to-a-vaiable

回答： Sarthak 2023-2-9

dead_load = input('Enter the value of Dead Load (in kN/m) = ');
    include_self_wght = input('Does the Dead Load include Self Weight? (1)Yes (2)No = ' );
    if include_self_wght == 1
        self_wght = 0;
    else
        self_wght = 25*(b/1000)*(D/1000);
    end
    if isempty(dead_load)
        dead_load = 6;
    end

I want the self wght to be 0 if the include_self-wght = 1

but whenever I run the code it always evaluates the expression irrespective of what the user has inputted

please help me

Thanks

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DGM 2023-1-28

I don't know what you were giving it, but when the user inputs "1", then self_wght is set to 0 as requested.

Bear in mind that the logic presented to the user is:

"1" is yes
"2" is no

... when in reality, it's

"1" is yes
any other number is no
any input that begins with a non-numeric character will not be accepted
any number followed by a non-numeric character will result in an error

If you're going to write your code around subjecting the user to a tedious series of input() prompts, you might want to think about the ergonomics of the affair from the user's perspective.

Ask the user for the specific information needed. If you need a binary flag that changes the program behavior, simply ask a yes/no question and check the leading character instead of asking the user to codify their own response in an arbitrary numeric format.

Safeguard against all the inputs that you might get, especially considering that this sort of interactive workflow is a great way to collect typos. This generally winds up making every instance of input() into a loop that tests for validity and re-prompts if the input is invalid.