Correct way of looping through C arrays

Question

Recently I have found a lot of examples  most of them regards the C   98  anyways I have created my simple-array and a loop  codepad     include  lt iostream gt  using namespace std   int main         string texts       Apple    Banana    Orange       for  unsigned int a   0  a  lt  sizeof texts   a   a   1               cout  lt  lt   value of a     lt  lt  texts a   lt  lt  endl           return 0      Output   value of a  Apple value of a  Banana value of a  Orange  Segmentation fault  It s working fine  except the segmentation fault at the end   My question is  does this array loop through is done a good way  I am using C   11 so would like to be sure it fits the standards and couldnt be done a better way

User · Answer

Add a stopping value to the array    include  lt iostream gt  using namespace std   int main         string texts       Apple    Banana    Orange           for  unsigned int a   0  texts a  length    a   a   1               cout  lt  lt   value of a     lt  lt  texts a   lt  lt  endl           return 0

User · Answer

You can do it as follow    include  lt  iostream  gt   using namespace std   int main          string texts       Apple    Banana    Orange        for  unsigned int a   0  a  lt  sizeof texts    32  a          32 is the size of string data type         cout  lt  lt   value of a     lt  lt  texts a   lt  lt  endl             return 0

User · Answer

How about    include  lt iostream gt   include  lt array gt   include  lt algorithm gt   int main          std  array lt std  string  3 gt  text     Apple    Banana    Orange        std  for each text begin    text end       std  string  amp string   std  cout  lt  lt  string  lt  lt    n            return 0      Compiles and works with C   11 and has no  raw  looping

User · Answer

sizeof tells you the size of a thing  not the number of elements in it  A more C  11 way to do what you are doing would be    include  lt array gt   include  lt string gt   include  lt iostream gt   int main         std  array lt std  string  3 gt  texts    Apple    Banana    Orange         for  auto amp  text   texts            std  cout  lt  lt  text  lt  lt    n             return 0      ideone demo  http   ideone com 6xmSrn

User · Answer

sizeof texts  on my system evaluated to 96  the number of bytes required for the array and its string instances   As mentioned elsewhere  the sizeof texts  sizeof texts 0   would give the value of 3 you were expecting

User · Answer

you need to understand difference between std  array  size and sizeof   operator  if you want loop to array elements in conventional way then you could use std  array  size  this will return number of elements in array but if you keen to use C  11 then prefer below code  for const string  amp text   texts      cout  lt  lt   value of text     lt  lt  text  lt  lt  endl

User · Answer

If you have a very short list of elements you would like to handle  you could use the std  initializer list introduced in C  11 together with auto    include  lt iostream gt   int main int  char           for const auto amp  ext       slice     socket     service     target             std  cout  lt  lt   Handling     lt  lt  ext  lt  lt    systemd files   lt  lt  std  endl       return 0

User · Answer

In C C   sizeof  always gives the number of bytes in the entire object  and arrays are treated as one object  Note  sizeof a pointer--to the first element of an array or to a single object--gives the size of the pointer  not the object s  pointed to  Either way  sizeof does not give the number of elements in the array  its length   To get the length  you need to divide by the size of each element  eg    for  unsigned int a   0  a  lt  sizeof texts  sizeof texts 0    a   a   1     As for doing it the C  11 way  the best way to do it is probably  for const string  amp text   texts      cout  lt  lt   value of text     lt  lt  text  lt  lt  endl    This lets the compiler figure out how many iterations you need   EDIT  as others have pointed out  std  array is preferred in C  11 over raw arrays  however  none of the other answers addressed why sizeof is failing the way it is  so I still think this is the better answer

User · Answer

string texts       Apple    Banana    Orange    for  unsigned int a   0  a  lt  sizeof texts   a   a   1         cout  lt  lt   value of a     lt  lt  texts a   lt  lt  endl      Nope  Totally a wrong way of iterating through an array  sizeof texts  is not equal to the number of elements in the array   The modern  C  11 ways would be to    use std  array if you want an array whose size is known at compile-time  or use std  vector if its size depends on runtime   Then use range-for when iterating    include  lt iostream gt   include  lt array gt    int main         std  array lt std  string  3 gt  texts     Apple    Banana    Orange             An array of 3 elements with the type std  string      for const auto amp  text   texts         Range-for          std  cout  lt  lt  text  lt  lt  std  endl            Live example    You may ask  how is std  array better than the ol  C array  The answer is that it has the additional safety and features of other standard library containers  mostly closely resembling std  vector  Further  The answer is that it doesn t have the quirks of decaying to pointers and thus losing type information  which  once you lose the original array type  you can t use range-for or std  begin end on it

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