C++23 Update We now finally have std::print as a way to use std::format for output directly: #include <print> #include <string> int main() { // … std::print(“Follow this command: {}”, myString); // … } This combines the best of both approaches. Original Answer It’s compiling because printf isn’t type safe, since it uses variable arguments in … Read more
printf‘s %b format specifier was meant specifically to replace echo -e (actually, the XSI extension to echo which calls for special interpretation of the arguments by default. -e was never specified and is disallowed by POSIX.), and is identical in virtually every way including a few differences from $’…’ and the format string argument to … 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
Sign extension. Your compiler is implementing char as a signed char. When you pass the chars to printf they are all being sign extended during their promotion to ints. When the first bit is a 0 this doesn’t matter, because it gets extended with 0s. 0xAF in binary is 10101111 Since the first bit is … Read more
The fact that GCC issues a warning usually has nothing to do with whether the construct is legal C, but whether the GCC developers consider it either a likely indication that you meant something other than what you write, or just bad style. Here are some examples: if (x = 0) — you almost surely … Read more
The C standard says that for the f and F floating point format specifiers: If a decimal-point character appears, at least one digit appears before it. I think that if you don’t want a zero to appear before the decimal point, you’ll probably have to do something like use snprintf() to format the number into … Read more
The code posted is incorrect: a_static and b_static should be defined as arrays. There are two ways to correct the code: you can add null terminators to make these arrays proper C strings: #include <stdio.h> int main(void) { char a_static[] = { ‘q’, ‘w’, ‘e’, ‘r’, ‘\0’ }; char b_static[] = { ‘a’, ‘s’, ‘d’, … 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.
%d prints an integer: it will print the ascii representation of your character. What you need is %c: printf(“%c”, ch); printf(“%d”, ‘\0’); prints the ascii representation of ‘\0’, which is 0 (by escaping 0 you tell the compiler to use the ascii value 0. printf(“%d”, sizeof(‘\n’)); prints 4 because a character literal is an int, … Read more