The so-called usual arithmetic conversions apply to many binary operators, but not all of them. For example they do not apply to the bit shift operators, &&, ||, comma operator, and assignment operators. This is the rule for the bit shift operators: 6.5.7 … 3 Semantics … The integer promotions are performed on each of … Read more
It has little to do with rank of the type defined in 4.13. 4.13 defined internal rankings used to describe integral promotions and usual arithmetic conversions. They by itself do not directly affect overload resolution. Rankings relevant to overload resolution are defined in “13.3.3.1.1 Standard conversion sequences” and then used in “13.3.3.2 Ranking implicit conversion … Read more
I purposefully did not compile and run then on my system, since this is the type of thing that could be compiler dependent. This is not compiler dependent. C++ clearly defines the order of these operations and how they are converted. How the conversion happens is dependent on the order of operations. double result1 = … Read more
Historical motivation: C The idea of integral promotions dates all the way back to pre-standard C. When providing arguments to variadic functions (…) or to functions without a prototype, promotions are applied. I.e. calling: // function declaration with no prototype void mystery(); // … char c=”c”; mystery(c); // this promotes c to int // in … Read more
This little test is actually more subtle than it looks as the behavior is implementation defined: unsigned char x = 255; no ambiguity here, x is an unsigned char with value 255, type unsigned char is guaranteed to have enough range to store 255. printf(“%x\n”, x); This produces ff on standard output but it would … Read more
This is because of the various implicit type conversion rules in C. There are two of them that a C programmer must know: the usual arithmetic conversions and the integer promotions (the latter are part of the former). In the char case you have the types (signed char) == (unsigned char). These are both small … Read more
If we look at the Rationale for International Standard—Programming Languages—C in section 6.3.1.8 Usual arithmetic conversions it says (emphasis mine going forward): The rules in the Standard for these conversions are slight modifications of those in K&R: the modifications accommodate the added types and the value preserving rules. Explicit license was added to perform calculations … Read more