how to print size of char pointer array?

[scoobydoo666]

Hi
Could any one tell me how to print size of char pointer array?
for example
char *ptrArray=new[25];
cout<<sizeof(ptrArray);
The above code will print 4 (pointer size) instead of 25. how do I print 25?

Thanks in advance

[Savage]

Hi
Could any one tell me how to print size of char pointer array?
for example
char *ptrArray=new[25];
cout<<sizeof(ptrArray);
The above code will print 4 (pointer size) instead of 25. how do I print 25?

Thanks in advance

U can't use sizeof for that.Sizeof returns sizeof variable on program stack memory,and as you know a pointer takes four bytes to be stored on stack.If you allocate dynamically,data that pointer is pointing to is on heap,not on stack.My question is why do you want to do that?If you allocate array dynamically u already know number of elements in it

[hsn]

he means you can't.
when you create an array you give the size of the array.
so you know it already.
there is other variables that you can check their sizes (which are like arrays)
vectors is the very known.
when you create a vector you don't need to give a size for it.
you just keep putting data init. and when you want to check its size you use a function (v.size()).

[scoobydoo666]

Hi Savage
I'm using strncpy() and strncat() to copy strings into the array. For this I want to know the size of the array and I don't want to hard code the size.
Instead of coding
char *ptrArray=new[25];
strncpy(ptrArray, sourceArray, 24); //24: array size hard coded
ptrArray[24]='\0';

I want to code
int arrSize=sizeof(ptrArray);
strncpy(ptrArray, sourceArray, arrSize-1);
ptrArray[arrSize-1]='\0';

So in future if array size is changed, no code change is required

[gpraghuram]

Hi Savage
I'm using strncpy() and strncat() to copy strings into the array. For this I want to know the size of the array and I don't want to hard code the size.
Instead of coding
char *ptrArray=new[25];
strncpy(ptrArray, sourceArray, 24); //24: array size hard coded
ptrArray[24]='\0';

I want to code
int arrSize=sizeof(ptrArray);
strncpy(ptrArray, sourceArray, arrSize-1);
ptrArray[arrSize-1]='\0';

So in future if array size is changed, no code change is required

Usually the practise is using #define the size and use the #define variable.
To get the size of the array we shuld use strlen.

Raghuram

[scoobydoo666]

Hi
I solved the problem by using constant int to define the array size. Thanks everyone for your reply.

[rjsherman1]

so you want to count the elements in the char pointer ... it's actually pretty easy to do ..

int size(char *ptr)
{ 
     int charCnt = 0;
     while (*str != '\0')
     {
          charCnt++;
          str++;
     }
 
     return charCnt;
}
 

granted the assumption here is that your counting the characters from a cstring -

frankly .. if you are copying string - why not just use the string.c_str() function which turns your string in a const char *pointer - that is the string.