How can I implement a variable field width with printf?

.NET C C++ CSS DBA General HTML Java JavaScript JSP JUnit MySQL Networking Oracle Perl Perl PHP PL/SQL RSS Software QA SQL Server Struts Unix Windows XHTML XML

Home Hot About Collections Index RSS Atom Ask

Tester Developer DBA Windows JAR DLL Files Certificates RegEx Links Q&A Biotech Phones Travel FAQ Forum

Home > C

How can I implement a variable field width with printf? That is, instead of something like %8d, I want the width to be specified at run time.

✍: Guest

printf("%*d", width, x) will do just what you want. The asterisk in the format specifier indicates that an int value from the argument list will be used for the field width. (Note that in the argument list, the width precedes the value to be printed.)

2021-01-21, 3567👍, 1💬

💬 2021-01-21 John Doe: Hello

How can I print numbers with commas separating the thousands? What about currency formatted numbers?
How can I print numbers with commas separating the thousands? What about currency formatted numbers? The functions in <locale.h> begin to provide some support for these operations, but there is no standard C function for doing either task. (In Standard C, the only thing printf does in respons... 2015-11-02, 1151👍, 0💬

Why doesnt the call scanf work?
Why doesn't the call scanf("%d", i) work? The arguments you pass to scanf must always be pointers: for each value converted, scanf ``returns'' it by filling in one of the locations you've passed pointers to. To fix the fragment above, change it to scanf("%d", &i) . 2015-11-02, 1015👍, 0💬

I thought that ANSI function prototypes were supposed to guard against argument type mismatches.
I thought that ANSI function prototypes were supposed to guard against argument type mismatches. When a function accepts a variable number of arguments, its prototype does not (and cannot) provide any information about the number and types of those variable arguments. Therefore, the usual protection... 2015-11-06, 1014👍, 0💬

How can printf use f for type double, if scanf requires lf?
Someone told me it was wrong to use %lf with printf. How can printf use %f for type double, if scanf requires %lf? It's true that printf's %f specifier works with both float and double arguments Due to the ``default argument promotions'' (which apply in variable-length argument lists values of type ... 2015-11-06, 1000👍, 0💬

Why doesnt long int work?
Why doesn't long int n = 123456; printf("%d\n", n); work? Whenever you print long ints you must use the l (lower case letter ``ell'') modifier in the printf format (e.g. %ld). printf can't know the types of the arguments which you've passed to it, so you must let it know by using the correct format ... 2015-11-09, 993👍, 0💬

How can I print a character in a printf format string?
How can I print a '%' character in a printf format string? I tried \%, but it didn't work. Simply double the percent sign: %% . The reason it's tricky to print % signs with printf is that % is essentially printf's escape character. Whenever printf sees a %, it expects it to be followed by a characte... 2015-11-09, 990👍, 0💬

What printf format should I use for a typedef like size_t when I don't know whether it is long or some other type?
What printf format should I use for a typedef like size_t when I don't know whether it is long or some other type? Use a cast to convert the value to a known, conservatively-sized type, then use the printf format matching that type. For example, to print the size of a type, you might use printf("%lu... 2015-11-04, 956👍, 0💬

Why doesnt this code work?
Why doesn't this code: double d; scanf("%f", &d); work? Unlike printf, scanf uses %lf for values of type double, and %f for float.%f tells scanf to expect a pointer-to-float, not the pointer-to-double you gave it. Either use %lf, or declare the receiving variable as a float. 2015-10-30, 920👍, 0💬

Why does the call char scanf work?
Why does the call char s[30]; scanf("%s", s); work? I thought you always needed an & on each variable passed to scanf. You always need a pointer; you don't necessarily need an explicit &. When you pass an array to scanf, you do not need the &, because arrays are always passed to func... 2015-10-30, 906👍, 0💬

.NET C C++ CSS DBA General HTML Java JavaScript JSP JUnit MySQL Networking Oracle Perl Perl PHP PL/SQL RSS Software QA SQL Server Struts Unix Windows XHTML XML

Home Hot About Collections Index RSS Atom Ask

Tester Developer DBA Windows JAR DLL Files Certificates RegEx Links Q&A Biotech Phones Travel FAQ Forum

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.