how to initialize a char array

Question

char   msg   new char 65546     want to initialize to 0 for all of them  what is the best way to do this in C

User · Accepted Answer

char   msg   new char 65546       It s known as value-initialisation  and was introduced in C  03  If you happen to find yourself trapped in a previous decade  then you ll need to use std  fill    or memset   if you want to pretend it s C    Note that this won t work for any value other than zero  I think C  0x will offer a way to do that  but I m a bit behind the times so I can t comment on that   UPDATE  it seems my ruminations on the past and future of the language aren t entirely accurate  see the comments for corrections

User · Answer

what is the best way to do this in   C      Because you asked it this way   std  string msg 65546  0      all characters will be set to 0   Or   std  vector lt char gt  msg 65546      all characters will be initialized to 0   If you are working with C functions which accept char  or const char   then you can do   some c function  amp msg 0      You can also use the c str   method on std  string if it accepts const char  or data     The benefit of this approach is that you can do everything you want to do with a dynamically allocating char buffer but more safely  flexibly  and sometimes even more efficiently  avoiding the need to recompute string length linearly  e g    Best of all  you don t have to free the memory allocated manually  as the destructor will do this for you

User · Answer

The C-like method may not be as attractive as the other solutions to this question  but added here for completeness   You can initialise with NULLs like this   char msg 65536     0     Or to use zeros consider the following   char msg 65536      0  another 65535 of these separated by comma     But do not try it as not possible  so use memset   In the second case  add the following after the memset if you want to use msg as a string    msg 65536 - 1       0    Answers to this question also provide further insight

User · Answer

This method uses the  C  memset function  and is very fast  avoids a char-by-char loop    const uint size   65546  char  msg   new char size   memset reinterpret cast lt void  gt  msg   0  size

User · Answer

Absent a really good reason to do otherwise  I d probably use   std  vector lt char gt  msg 65546    0

User · Answer

memset msg  0  65546

User · Answer

The  most C    way to do this would be to use std  fill   std  fill msg  msg   65546  0

User · Answer

You can use a for loop  but don t forget the last char must be a null character    char   msg   new char 65546   for int i 0 i lt 65545 i          msg i   0     msg 65545    0

[c++] how to initialize a char array?

Examples related to c++

Examples related to visual-c++