Is there a function to copy an array in C C

Question

I am a Java programmer learning C C    So I know that Java has a function like System arraycopy    to copy an array  I was wondering if there is a function in C or C   to copy an array  I was only able to find implementation to copy an array by using for loop  pointers etc  Is there a function that I can use to copy an array

User · Answer

In C you can use memcpy  In C   use std  copy from the  lt algorithm gt  header

User · Answer

You can use the memcpy      void   memcpy   void   destination  const void   source  size t num      memcpy   copies the values of num bytes from the location pointed by source directly to the memory block pointed by destination   If the destination and source overlap  then you can use memmove      void   memmove   void   destination  const void   source  size t num      memmove   copies the values of num bytes from the location pointed by source to the memory block pointed by destination  Copying takes place as if an intermediate buffer were used  allowing the destination and source to overlap

User · Answer

Since you asked for a C   solution      include  lt algorithm gt   include  lt iterator gt   const int arr size   10  some type src arr size          some type dest arr size   std  copy std  begin src   std  end src   std  begin dest

User · Answer

Firstly  because you are switching to C    vector is recommended to be used instead of traditional array   Besides  to copy an array or vector  std  copy is the best choice for you   Visit this page to get how to use copy function  http   en cppreference com w cpp algorithm copy  Example   std  vector lt int gt  source vector  source vector push back 1   source vector push back 2   source vector push back 3   std  vector lt int gt  dest vector source vector size     std  copy source vector begin    source vector end    dest vector begin

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Use memcpy in C  std  copy in C

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Just include the standard library in your code    include lt algorithm gt    Array size will be denoted as n  Your old Array   int oldArray n   10 20 30 40 50     Declare New Array in which you have to copy your old array value  int newArray n     Use this  copy n oldArray n newArray

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As others have mentioned  in C you would use memcpy  Note however that this does a raw memory copy  so if your data structures have pointer to themselves or to each other  the pointers in the copy will still point to the original objects   In C   you can also use memcpy if your array members are POD  that is  essentially types which you could also have used unchanged in C   but in general  memcpy will not be allowed  As others mentioned  the function to use is std  copy   Having said that  in C   you rarely should use raw arrays  Instead you should either use one of the standard containers  std  vector is the closest to a built-in array  and also I think the closest to Java arrays     closer than plain C   arrays  indeed      but std  deque or std  list may be more appropriate in some cases  or  if you use C  11  std  array which is very close to built-in arrays  but with value semantics like other C   types  All the types I mentioned here can be copied by assignment or copy construction  Moreover  you can  cross-copy  from opne to another  and even from a built-in array  using iterator syntax   This gives an overview of the possibilities  I assume all relevant headers have been included    int main          This works in C and C     int a       1  2  3  4      int b 4     memcpy b  a  4 sizeof int       int is a POD       This is the preferred method to copy raw arrays in C   and works with all types that can be copied    std  copy a  a 4  b         In C  11  you can also use this    std  copy std  begin a   std  end a   std  begin b          use of vectors   std  vector lt int gt  va a  a 4      copies the content of a into the vector   std  vector lt int gt  vb   va        vb is a copy of va       this initialization is only valid in C  11    std  vector lt int gt  vc   5  6  7  8       note  no equal sign        assign vc to vb  valid in all standardized versions of C      vb   vc       alternative assignment  works also if both container types are different   vb assign vc begin    vc end        std  vector lt int gt  vd     an  empty  vector       you also can use std  copy with vectors      Since vd is empty  we need a  back inserter   to create new elements    std  copy va begin    va end    std  back inserter vd          copy from array a to vector vd       now vd already contains four elements  so this new copy doesn t need to      create elements  we just overwrite the existing ones    std  copy a  a 4  vd begin           C  11 only  Define a  std  array     std  array lt int  4 gt  sa     9  10  11  12          create a copy    std  array lt int  4 gt  sb   sa        assign the array    sb   sa

User · Answer

I give here 2 ways of coping array  for C and C   language  memcpy and copy both ar usable on C   but copy is not usable for C  you have to use memcpy if you are trying to copy array in C    include  lt stdio h gt   include  lt iostream gt   include  lt algorithm gt     for using copy  library function   include  lt string h gt     for using memcpy  library function    int main         int arr      1  1  2  2  3  3       int brr 100        int len   sizeof arr  sizeof  arr      finding size of arr  array       std   copy arr  arr len  brr      which will work on C   only  you have to use  include  lt algorithm gt      memcpy brr  arr  len  sizeof int        which will work on both C and C        for int i 0  i lt len  i        Printing brr  array           std   cout  lt  lt  brr i   lt  lt                  return 0

User · Answer

Since C  11  you can copy arrays directly with std  array   std  array lt int 4 gt  A    10 20 30 40   std  array lt int 4 gt  B   A    copy array A into array B   Here is the documentation about std  array

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I like the answer of Ed S   but this only works for fixed size arrays and not when the arrays are defined as pointers  So  the C   solution where the arrays are defined as pointers   include lt algorithm gt      const int bufferSize   10  char  origArray  newArray  std  copy origArray  origArray   bufferSize  newArray    Note  No need to deduct buffersize with 1    Copies all elements in the range  first  last  starting from first and proceeding to last - 1   See  https   en cppreference com w cpp algorithm copy

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in C  11 you may use Copy   that works for std containers  template  lt typename Container1  typename Container2 gt  auto Copy Container1 amp  c1  Container2 amp  c2      - gt  decltype c2 begin          auto it1   std  begin c1       auto it2   std  begin c2        while  it1    std  end c1              it2      it1              return it2

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