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Calloc C++

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# 1  
Old 08-04-2011
Calloc C++
Hello all,

I have a confusion with calloc function :

wz. the difference between the following 2 statemnts:

HTML Code:
char *ptr;
 
char = (char*)calloc(num, sizeof(char));
 
char = (char*)calloc(num, sizeof(char*));
Am really confused!!!!!

---------- Post updated at 09:32 AM ---------- Previous update was at 09:29 AM ----------

Sorry they are :

HTML Code:
ptr = (char*)calloc(num, sizeof(char));
 
ptr = (char*)calloc(num, sizeof(char*));
# 2  
Old 08-04-2011
Well, the obvious thing is to check:

Code:
printf("char = %d\n", sizeof(char));
printf("char * = %d\n", sizeof(char *));

Code:
char = 1
char * = 4

You've discovered the difference between a character, and a pointer to a character. The pointer is a memory address (4 bytes on 32-bit x86) that can be used to point to other memory.

Since you've declared a char *, it's a safe bet you want a pointer to characters, not a pointer to pointers, so use the first one.
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