18,446,744,073,709,551,615 This number mentioned, 18,446,744,073,709,551,615, is actually 2^64 − 1. The important thing here is that 2^64-1 is essentially 0-based 2^64. The first digit of an unsigned integer is 0, not 1. So if the maximum value is 1, it has two possible values: 0, or 1 (2). Let’s look at 2^64 – 1 in … Read more
When comparing signed with unsigned, the compiler converts the signed value to unsigned. For equality, this doesn’t matter, -1 == (unsigned) -1. For other comparisons it matters, e.g. the following is true: -1 > 2U. EDIT: References: 5/9: (Expressions) Many binary operators that expect operands of arithmetic or enumeration type cause conversions and yield result … Read more
Assign a int -1 to an unsigned: As -1 does not fit in the range [0…UINT_MAX], multiples of UINT_MAX+1 are added until the answer is in range. Evidently UINT_MAX is pow(2,32)-1 or 429496725 on OP’s machine so a has the value of 4294967295. unsigned int a = -1; The “%x”, “%u” specifier expects a matching … Read more
UNSIGNED is an attribute which can be added to many types. From the documentation: data_type: BIT[(length)] | TINYINT[(length)] [UNSIGNED] [ZEROFILL] | SMALLINT[(length)] [UNSIGNED] [ZEROFILL] | MEDIUMINT[(length)] [UNSIGNED] [ZEROFILL] | INT[(length)] [UNSIGNED] [ZEROFILL] | INTEGER[(length)] [UNSIGNED] [ZEROFILL] | BIGINT[(length)] [UNSIGNED] [ZEROFILL] | REAL[(length,decimals)] [UNSIGNED] [ZEROFILL] | DOUBLE[(length,decimals)] [UNSIGNED] [ZEROFILL] | FLOAT[(length,decimals)] [UNSIGNED] [ZEROFILL] | DECIMAL[(length[,decimals])] [UNSIGNED] … Read more
The actual issue here is that use of unary minus operator, just like the rest of built-in arithmetic operators, is a subject to integral promotions. So surprisingly the result of applying unary minus to size_t will be still size_t and there is no need to blame auto. Counter-example. In this case due to integral promotions … Read more
Using Google to search for “Visual Studio printf unsigned __int64” produces this page as the first result, which says you can use the prefix I64, so the format specifier would be %I64u.
When I needed this functionality inside of jOOQ, I haven’t found anything like it, so I rolled my own Open Source library that I call jOOU (U for Unsigned): http://github.com/jOOQ/jOOU I understand that some may think this is overkill, but I’d really like to have precisely those wrappers wrapping what other languages call ubyte, ushort, … Read more
The “%d” format is for (signed) int values. If you use it with an unsigned value, it could print something other than the actual value. Use “%u” to see the actual value, or %x to see it in hexadecimal. In the declaration unsigned int x = -1; the expression -1 is of type int, and … Read more
In Java 8, unsigned long support was introduced. Still, these are typical longs, but the sign doesn’t affect adding and subtracting. For dividing and comparing, you have dedicated methods in Long. Also, you can do the following: long l1 = Long.parseUnsignedLong(“12345678901234567890”); String l1Str = Long.toUnsignedString(l1) BigInteger is a bit different. It can keep huge numbers. … Read more
The draft C++ standard has the following footnote 296 in section 27.5.2 Types which says: streamsize is used in most places where ISO C would use size_t. Most of the uses of streamsize could use size_t, except for the strstreambuf constructors, which require negative values. It should probably be the signed type corresponding to size_t … Read more