Hi, I am asking the user for input and the input should be either "AA" "Aa" or "aa". How can I validate the input using a while loop? I don't think my code works.Thanks!

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Lavitania Searjaya
Lavitania Searjaya 2020-9-23
评论： Walter Roberson 2020-9-24
parentOneA = input("Enter Parent 1's A Trait: ")
% Error checking input
while parentOneA ~= "AA" || parentOneA ~= "Aa" || parentOneA ~= "aa";
parentOneA = input("Enter Parent 1's A Trait: ")
end
  2 个评论
Stephen23
Stephen23 2020-9-24
编辑：Stephen23 2020-9-24
There is no string for which this will return false:
parentOneA ~= "AA" || parentOneA ~= "Aa" || parentOneA ~= "aa";
At least two equality operators will return true, so the output will always be true because you used OR:
true || false || true -> true
Rather than writing them out individually, a better approach is to simply use strcmpi:
while ~strcmpi(parentOneA,'AA')

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回答（1 个）

Sindar
Sindar 2020-9-24
You're requiring that it be all valid entries simultaneously
parentOneA = input("Enter Parent 1's A Trait: ")
% Error checking input
while parentOneA ~= "AA" && parentOneA ~= "Aa" && parentOneA ~= "aa";
parentOneA = input("Enter Parent 1's A Trait: ")
end
or
valid_inputs = {'AA';'Aa';'aa'};
parentOneA = input("Enter Parent 1's A Trait: ")
while ~any(strcmp(parentOneA,valid_inputs))
parentOneA = input("Enter Parent 1's A Trait: ")
end

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