How can I open files with names like ...

.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 open files with names like ``file1'', ``file2'', ``file3'', etc., where the numeric part is controlled by a variable? Basically I want ``file%d'', like printf..

✍: Guest

You want printf's close cousin sprintf, which ``prints'' to a string:
char filename[FILENAME_MAX];
sprintf(filename, "file%d", i);
fp = fopen(filename, "r");

2015-10-07, 1387👍, 0💬

If fflush wont work, what can I use to flush input?
If fflush wont work, what can I use to flush input? It depends on what you're trying to do. If you're trying to get rid of an unread newline or other unexpected input after calling scanf you really need to rewrite or replace the call to scanf. Alternatively, you can consume the rest of a partially-r... 2015-10-12, 1497👍, 0💬

Once I have used freopen, how can I get the original stdout (or stdin) back?
Once I have used freopen, how can I get the original stdout (or stdin) back? There isn't a good way. If you need to switch back, the best solution is not to have used freopen in the first place. Try using your own explicit output (or input) stream variable, which you can reassign at will, while leav... 2015-10-01, 1468👍, 0💬

How can I insert or delete a line (or record) in the middle of a file?
How can I insert or delete a line (or record) in the middle of a file? In general, there is no way to do this. The usual solution is simply to rewrite the file. When you find yourself needing to insert data into an existing file, here are a few alternatives you can try: * Rearrange the data file so ... 2015-10-05, 1441👍, 0💬

How can I flush pending input so that a user ...
How can I flush pending input so that a user's typeahead isn't read at the next prompt? Will fflush(stdin) work? fflush is defined only for output streams. Since its definition of ``flush'' is to complete the writing of buffered characters (not to discard them), discarding unread input would not be ... 2015-10-12, 1435👍, 0💬

I am trying to update a file in place ...
I'm trying to update a file in place, by using fopen mode "r+", reading a certain string, and writing back a modified string, but it's not working. Be sure to call fseek before you write, both to seek back to the beginning of the string you're trying to overwrite, and because an fseek or fflush is a... 2015-10-07, 1404👍, 0💬

How can I tell if standard input or output is redirected
How can I tell if standard input or output is redirected (i.e. whether ``<'' or ``>'' was used on the invocation command line)? You can't tell directly, but you can usually look at a few other things to make whatever decision you need to. If you want your program to take input from std... 2015-10-01, 1391👍, 0💬

How can I open files with names like ...
How can I open files with names like ``file1'', ``file2'', ``file3'', etc., where the numeric part is controlled by a variable? Basically I want ``file%d'', like printf.. You want printf's close cousin sprintf, which ``prints'' to a string: char filename[FILENAME_MAX]; sprintf(filename, "file%d", i)... 2015-10-07, 1388👍, 0💬

I cant even get a simple fopen call to work
I can't even get a simple fopen call to work! What's wrong with this call? FILE *fp = fopen(filename, 'r'); fopen's mode argument must be a string, like "r", not a character like 'r'. 2015-10-09, 1368👍, 0💬

How can I recover the file name given an open stream?
How can I recover the file name given an open stream? This problem is, in general, insoluble. Under Unix, for instance, a scan of the entire disk (perhaps involving special permissions) would theoretically be required, and would fail if the descriptor were connected to a pipe or referred to a delete... 2015-10-05, 1337👍, 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.