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ex: input = 2424, output = 4
static int intlen(int n)
{
if (n == 0) return 1;
else if (n < 0) return 2 + static_cast<std::size_t>(std::log10(-n));
else if (n > 0) return 1 + static_cast<std::size_t>(std::log10(n));
}
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unsigned int number_of_digits = 0;
do {
++number_of_digits;
n /= base;
} while (n);