Help with simple do while function in C?

hey guys, so here is how the program works.
when the user enters any letter besides m or f, it should ask the question again. if the user enters m or f, then the program proceeds. In this situation, when the user enters m, the program proceeds, but when the user enters f, the program repeats the question again. Why is that, and how do i fix this? I tried using the OR ( the two vertical bars) but that didnt work either.

Code:

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do{
printf("What's your gender? Enter m or f >>> ");
scanf(" %c", &gender);
}
       
while (gender != 'm' && 'f');

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Wrong; does not work in C the way you think.

Code:

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while (gender != 'm' && 'f');

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Code:

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while (gender != 'm' && gender != 'f');

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Tim S.

Thanks Tim! quick question: if i wanted to add more variables, such as x, y, z, etc, then i would have to type out gender !='x' && gender !='y' && gender !='z' ? or is there a short cut to this that i am unaware about?

Quote:

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Originally Posted by yoyoyo

Thanks Tim! quick question: if i wanted to add more variables, such as x, y, z, etc, then i would have to type out gender !='x' && gender !='y' && gender !='z' ? or is there a short cut to this that i am unaware about?

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That is the way I do it. I know of no short cut.

Tim S.

Quote:

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Originally Posted by yoyoyo

Thanks Tim! quick question: if i wanted to add more variables, such as x, y, z, etc, then i would have to type out gender !='x' && gender !='y' && gender !='z' ? or is there a short cut to this that i am unaware about?

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Sometimes you can simplify logical expressions with Boolean Algebra, but not in this case -> You can make it look different:

Code:

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g!=x && g!=y && g!=z
is the same as
!(g==x || g==y || g==z)

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Quote:

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Originally Posted by yoyoyo

if i wanted to add more variables, such as x, y, z, etc, then i would have to type out gender !='x' && gender !='y' && gender !='z' ? or is there a short cut to this that i am unaware about?

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Using strchr() you could write it as:

Code:

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while (!strchr("xyz", gender));

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Bye, Andreas

Thank you everyone for your help!