If integer needs two bytes of storage, then maximum value of an unsigned integer is

An integer is a number with no fractional part; it can be positive, negative or zero. In ordinary usage, one uses a minus sign to designate a negative integer. However, a computer can only store information in bits, which can only have the values zero or one. We might expect, therefore, that the storage of negative integers in a computer might require some special technique. As you might imagine, an unsigned integer is either positive or zero. Consider a single digit decimal number: In a single decimal digit, you can write a number between 0 and 9. In two decimal digits, you can write a number between 0 and 99, and so on. Since nine is equivalent to 10¹ - 1, 99 is equivalent to 10² - 1, etc. In n decimal digits, you can write a number between 0 and 10ⁿ - 1. So, analogously, in the binary number system, An unsigned integer containing n bits can have a value between 0 and 2ⁿ - 1 (which is 2ⁿ different values).