An enum is guaranteed to be represented by an integer, but the actual type (and its signedness) is implementation-dependent. You can force an enumeration to be represented by a signed type by giving one of the enumerators a negative value: enum SignedEnum { a = -1 }; In C++0x, the underlying type of an enumeration … Read more
There are three distinct basic character types: char, signed char and unsigned char. Although there are three character types, there are only two representations: signed and unsigned. The (plain)char uses one of these representations. Which of the other two character representations is equivalent to char depends on the compiler. In an unsigned type, all the … Read more
There are three distinct basic character types: char, signed char and unsigned char. Although there are three character types, there are only two representations: signed and unsigned. The (plain)char uses one of these representations. Which of the other two character representations is equivalent to char depends on the compiler. In an unsigned type, all the … Read more
I don’t know about studies and statistics, but yes, there are definitely optimizations taking this into account that compilers actually do. And yes, they are very important (tldr loop vectorization for example). Besides the compiler optimizations, there is another aspect to be taken into account. With UB you get C/C++ signed integers to behave arithmetically … Read more
len() (and cap()) return int because that is what is used to index slices and arrays (not uint). So the question is more “Why does Go use signed integers to index slices/arrays when there are no negative indices?”. The answer is simple: It is common to compute an index and such computations tend to underflow … Read more
Because the int value is promoted to an unsigned int. specifically 0xFFFFFFFC on a 32-bit machine, which as an unsigned int is 4294967292, considerably larger than 10 C99 6.3.1.1-p2 If an int can represent all values of the original type (as restricted by the width, for a bit-field), the value is converted to an int; … Read more
No, addresses aren’t always positive – on x86_64, pointers are sign-extended and the address space is clustered symmetrically around 0 (though it is usual for the “negative” addresses to be kernel addresses). However the point is mostly moot, since C only defines the meaning of < and > pointer comparisons between pointers that are to … Read more
Android Export aborted because fatal error were founds [closed]
Just using int everywhere may seem tempting, since it minimizes the need for casting, but there are several potential pitfalls you should be aware of: An int might be shorter than you expect. Even though, on most desktop platforms, an int is typically 32 bits, the C standard only guarantees a minimum length of 16 … Read more
Binary operations between different integral types are performed within a “common” type defined by so called usual arithmetic conversions (see the language specification, 6.3.1.8). In your case the “common” type is unsigned int. This means that int operand (your b) will get converted to unsigned int before the comparison, as well as for the purpose … Read more