How to empty a char array

Question

Have an array of chars like char members 255   How can I empty it completely without using a loop   char members 255     By  empty  I mean that if it had some values stored in it then it should not  For example if I do strcat then old value should not remain  members    old value      empty it efficiently strcat members  new       should return only new and not  old value new

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EDIT  Given the most recent edit to the question  this will no longer work as there is no null termination - if you tried to print the array  you would get your characters followed by a number of non-human-readable characters  However  I m leaving this answer here as community wiki for posterity   char members 255      0      That should work  According to the C Programming Language      If the array has fixed size  the number of initializers may not exceed the number of members of the array  if there are fewer  the remaining members are initialized with 0    This means that every element of the array will have a value of 0  I m not sure if that is what you would consider  empty  or not  since 0 is a valid value for a char

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Don t bother trying to zero-out your char array if you are dealing with strings  Below is a simple way to work with the char strings   Copy  assign new string    strcpy members   hello      Concatenate  add the string    strcat members    world      Empty string   members 0    0    Simple like that

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You cannot empty an array as such  it always contains the same amount of data   In a bigger context the data in the array may represent an empty list of items  but that has to be defined in addition to the array  The most common ways to do this is to keep a count of valid items  see the answer by pmg  or for strings to terminate them with a zero character  the answer by Felix   There are also more complicated ways  for example a ring buffer uses two indices for the positions where data is added and removed

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members 0    0    is enough  given your requirements   Notice however this is not  emptying  the buffer  The memory is still allocated  valid character values may still exist in it  and so forth

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I d go with  members in use   0

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I had similar problem  I was trying to display results of Analog to Digital value from a Char type Array   The problem was when I was turning the Pot to get lower voltage or lower converted decimal value like 5 from between  1023 - 0   the lift over characters from array was staying beside the number 5   I used this method to get rid of the problem  LCD Send String  quot      quot                 used spaces as string characters LCD Send Command  LCD THIRD ROW      Returned the cursor back at the start of line

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You can use the following instruction   strcpy s members

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char members 255     0

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Use bzero array name  no of bytes to be cleared

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simpler is better - make sense   in this case just members 0    0 works  don t make a simple question so complicated

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Disclaimer  I don t usually program in C so there may be any syntax gotcha in my examples  but I hope the ideas I try to express are clear   If  emptying  means  containing an empty string   you can just assign the first array item to zero  which will effectively make the array to contain an empry string   members 0    0    If  emptying  means  freeing the memory it is using   you should not use a fixed char array in the first place  Rather  you should define a pointer to char  and then do malloc   free  or string assignment  as appropriate   An example using only static strings   char  emptyString     char  members     Set string value members    old value      Empty string value member   emptyString    Will return just  new  strcat members  new

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By  empty an array  if you mean reset to 0  then you can use bzero      include  lt strings h gt    void bzero void  s  size t n       If you want to fill the array with some other default character then you may use memset function      include  lt string h gt    void  memset void  s  int c  size t n

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using    memset members  0  255     in general    memset members  0  sizeof members     if the array is in scope  or     memset members  0  nMembers    sizeof members 0        if you only have the pointer value  and nMembers is the number of elements in the array     EDIT Of course  now the requirement has changed from the generic task of clearing an array to purely resetting a string  memset is overkill and just zeroing the first element suffices  as noted in other answers      EDIT In order to use memset  you have to include string h

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Depends on what you mean by  empty    members 0      0

[c] How to empty a char array?

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