The short answer is that it has no impact on printf, and denotes use of float or double in scanf. For printf, arguments of type float are promoted to double so both %f and %lf are used for double. For scanf, you should use %f for float and %lf for double. More detail for the … Read more
You’re doing it right. From the manual page: o, u, x, X The unsigned int argument is converted to unsigned octal (o), unsigned decimal (u), or unsigned hexadecimal (x and X) notation. So the value for x should always be unsigned. To make it long in size, use: l (ell) A following integer conversion corresponds … Read more
Your output is being buffered. You have 4 options: explicit flush fflush after each write to profit from the buffer and still enforce the desiredbehavior/display explicitly. fflush( stdout ); have the buffer only buffer lines-wise useful for when you know that it is enough to print only complete lines setlinebuf(stdout); disable the buffer setbuf(stdout, NULL); … Read more
What you’re looking for is reflection. Java and other virtual languages has reflection so you can print out the variable names and function names for any given class. Because the compiler builds these reflection functions automatically. C does not have reflection. You must do everything manually.
It’s %td. See here.
You can use the + flag of printf to print positive numbers with a leading + sign as: printf(“%+d %+d”,10,-10); // prints +10 -10
Checking if 2 printf() format strings are compatible is an exercise in format parsing. C, at least, has no standard run-time compare function such as: int format_cmp(const char *f1, const char *f2); // Does not exist Formats like “%d %f” and “%i %e” are obviously compatible in that both expect an int and float/double. Note: … Read more
In C++ the macros are not automatically defined just by including the file. You need to add the following: #define __STDC_FORMAT_MACROS 1 before #include <inttypes.h> How to printf uint64_t? Fails with: “spurious trailing ‘%’ in format”
Why is printf(“%8d\n”, intval); not working for you? It should… You did not show the format strings for any of your “not working” examples, so I’m not sure what else to tell you. #include <stdio.h> int main(void) { int i; for (i = 1; i <= 10000; i*=10) { printf(“[%8d]\n”, i); } return (0); } … Read more