Include <stdbool.h> header #include <stdbool.h> int main(void){ bool b = false; } Macros true and false expand to 1 and 0 respectively. Section 7.16 Boolean type and values < stdbool.h > 1 The header <stdbool.h> defines four macros. 2 The macro bool expands to _Bool. 3 The remaining three macros are suitable for use in … Read more
MS has a series of public replies to this, most of them blaming their users. Like this one: https://devblogs.microsoft.com/cppblog/iso-c-standard-update/ Now, the Visual C++ compiler team receives the occasionally question as to why we haven’t implemented C99. It’s really based on interest from our users. Where we’ve received many requests for certain C99 features, we’ve tried … Read more
It is always one in C99, section 6.5.3.4: When applied to an operand that has type char, unsigned char, or signed char, (or a qualified version thereof) the result is 1. Edit: not part of your question, but for interest from Harbison and Steele’s. C: A Reference Manual, Third Edition, Prentice Hall, 1991 (pre c99) … Read more
Actually this excellent answer also answers your question, I think: What does extern inline do? The idea is that “inline” can be used in a header file, and then “extern inline” in a .c file. “extern inline” is just how you instruct the compiler which object file should contain the (externally visible) generated code. [update, … Read more
Turns out you can download a MS version of this header from: https://github.com/mattn/gntp-send/blob/master/include/msinttypes/stdint.h A portable one can be found here: http://www.azillionmonkeys.com/qed/pstdint.h Thanks to the Software Ramblings blog. NB: The Public Domain version of the header, mentioned by Michael Burr in a comment, can be find as an archived copy here. An updated version can be … Read more
C99 allows //-style comments, C89 does not. So, to translate: C99: printf(“C%d\n”,(int)(90-(-4.5 /*Some comment stuff*/ -4.5))); // Outputs: 99 C89: printf(“C%d\n”,(int)(90-(-4.5/ -4.5))); /* so we get 90-1 or 89 */
Obviously a hack… but a way of squaring a number without using the * operator (this was a coding contest requirement). (&a)[n] is equivalent to a pointer to int at location (a + sizeof(a[n])*n) and thus the entire expression is (&a)[n] -a = (a + sizeof(a[n])*n -a) /sizeof(int) = sizeof(a[n])*n / sizeof(int) = sizeof(int) * … Read more
On July 15 ’17 P0329R4 was accepted into the c++20 standard: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0329r4.pdf This brings limited support for c99’s Designated Initializers. This limitation is described as follows by C.1.7[diff.decl].4, given: struct A { int x, y; }; struct B { struct A a; }; The following Designated Initializations, which are valid in C, are restricted in … Read more
I recommend @Jens Gustedt hexadecimal solution: use %a. OP wants “print with maximum precision (or at least to the most significant decimal)”. A simple example would be to print one seventh as in: #include <float.h> int Digs = DECIMAL_DIG; double OneSeventh = 1.0/7.0; printf(“%.*e\n”, Digs, OneSeventh); // 1.428571428571428492127e-01 But let’s dig deeper … Mathematically, the … Read more
Everything before standardization is generally called “K&R C”, after the famous book (1st edition and 2nd edition), with Dennis Ritchie, the inventor of the C language, as one of the authors. This was “the C language” from 1972-1989. The first C standard was released 1989 nationally in USA, by their national standard institute ANSI. This … Read more