System.out is a PrintStream, and quoting the javadoc for PrintStream.printf An invocation of this method of the form out.printf(l, format, args) behaves in exactly the same way as the invocation out.format(l, format, args)
It’s platform-specific. But you can cast it to a known type. printf(“%lld\n”, (long long) time(NULL));
With the %f format specifier, the “2” is treated as the minimum number of characters altogether, not the number of digits before the decimal dot. Thus you have to replace it with 4 to get two leading digits + the decimal point + one decimal digit. printf(“%d:%02d:%04.1f hours\n”, 1, 4, 2.123456);
There’s no such specifier. I think what you’re doing (casting the pid_t to long and printing it with “%ld”) is fine; you could use an even wider int type, but there’s no implementation where pid_t is bigger than long and probably never will be.
MS Visual Studio didn’t support %zu printf specifier before VS2013. Starting from VS2013 (e.g. _MSC_VER >= 1800) %zu is available. As an alternative, for previous versions of Visual Studio if you are printing small values (like number of elements from std containers) you can simply cast to an int and use %d: printf(“count: %d\n”, (int)str.size()); … Read more
m conversion specifier is not C but is a GNU extension to printf: From GNU documentation: http://www.gnu.org/software/libc/manual/html_node/Other-Output-Conversions.html The ‘%m’ conversion prints the string corresponding to the error code in errno. See Error Messages. Thus: fprintf (stderr, “can’t open `%s’: %m\n”, filename); is equivalent to: fprintf (stderr, “can’t open `%s’: %s\n”, filename, strerror (errno)); The ‘%m’ … Read more
In C++20 you can use std::format for safe printf-like formatting: std::cout << std::format(“The answer is {}.\n”, 42); In addition to that the {fmt} library, std::format is based on, provides the print function that combines formatting and output: fmt::print(“The answer is {}.\n”, 42); Disclaimer: I’m the author of {fmt} and C++20 std::format.
As a string, no. As an integer, %d. Unless you count: static char* enumStrings[] = { /* filler 0’s to get to the first value, */ “enum0”, “enum1”, /* filler for hole in the middle: ,0 */ “enum2”, “enum3”, …. }; … printf(“The value is %s\n”, enumStrings[thevalue]); This won’t work for something like an enum … Read more
C does not and never has had a native string type. By convention, the language uses arrays of char terminated with a null char, i.e., with ‘\0′. Functions and macros in the language’s standard libraries provide support for the null-terminated character arrays, e.g., strlen iterates over an array of char until it encounters a ‘\0’ … Read more
It’s used to specify, in a dynamic way, what the width of the field is: The width is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted. so “indent” specifies how much space to allocate for the string that follows it in the … Read more