conditional statements - Why is my c != 'o' || c != 'x' condition always true?

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Answer 1

The condition (c != 'o' || c != 'x') can never be false. If c is 'o', then c != 'x' will be true and the OR condition is satisfied. If c is 'x', then c != 'o' will be true and the OR condition is satisfied.

You want && (AND), not || (OR):

while (c != 'o' && c != 'x') {
    // ...
}

"While c is NOT 'o' AND c is NOT `'x'..." (e.g., it's neither of them).

Or use De Morgan's law, covered here:

while (!(c == 'o' || c == 'x')) {
    // ...
}

"While it's NOT true that (c is 'o' or c is 'x')..."