The accepted convention of passing C-strings to functions is to use a pointer: When the function modifies the string you should also pass in the length: Your first example: passes an array of pointers to strings which is not what you need at all. Your second example: passes an array of chars. The size of … Read more
Why do we use NULL in strok() function? What does this program do when *h is pointing to a string?
The first code sample is pretty much a classis for loop. Its complexity is O(n^2). This is because the inner loop has a complexity O(n) and it is run n times. The second one is a bit more difficult, untill you see that is equivalent to a non nested loop (ignoring the complexity of the … Read more
Sounds like you’re expecting size_t to be the same as unsigned long (possibly 64 bits) when it’s actually an unsigned int (32 bits). Try using %zu in both cases. I’m not entirely certain though.
In Lua 5.2 or earlier, both tostring(10) and tostring(10.0) result as the string “10”. In Lua 5.3, this has changed: That’s because Lua 5.3 introduced the integer subtype. From Changes in the Language: The conversion of a float to a string now adds a .0 suffix to the result if it looks like an integer. (For instance, the float 2.0 will be printed as 2.0, not … Read more
i am having a probem with valgrind givin me an error saying “Access not within mapped region at address 0x8”. It then says “at 0x400606: append_linked_list (testing2.c:64) by 0x400563: main (testing2.c:32)”. Line 64 is list->tail->next = newNode;, and line 32 is just calling the function which line 64 is in append_linked_list(list, (void *) argv[i]);. When … Read more
Padding aligns structure members to “natural” address boundaries – say, int members would have offsets, which are mod(4) == 0 on 32-bit platform. Padding is on by default. It inserts the following “gaps” into your first structure: Packing, on the other hand prevents compiler from doing padding – this has to be explicitly requested – under GCC it’s __attribute__((__packed__)), so the following: … Read more
The steps: The autogen.sh script generates the configure script (from configure.ac, using autoconf) and any files it needs (like creating Makefile.in from Makefile.am using automake). This requires autotools to be installed on your system, and it must be run when checking out the project from source control (if configure isn’t checked in). People who download source tarballs can usually skip this step, because output of this … Read more
The getint() function only reads digits from the input. If it gets a character that is not a digit or a + – sign at the beginning it will call ungetch() to push the character back into the input buffer so it could be read by some other function call. getint() will go on returning … Read more
From the Advanced Programming in Unix Environment: … The difference between getc and fgetc is that getc can be implemented as a macro, whereas fgetc cannot be implemented as a macro. This means three things: The argument to getc should not be an expression with side effects. Since fgetc is guaranteed to be a function, we can take its address. This allows us to pass the address of fgetc as … Read more