Question about pointers and strings in C [duplicate]

Question

Possible Duplicate:
What is the difference between char s[] and char *s in C?
Difference between char *str = “…” and char str[N] = “…”?

I have some code that has had me puzzled.

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
  char* string1 = "this is a test";
  char string2[] = "this is a test";
  printf("%i, %i\n", sizeof(string1), sizeof(string2));
  system("PAUSE"); 
  return 0;
}

When it outputs the size of string1, it prints 4, which is to be expected because the size of a pointer is 4 bytes. But when it prints string2, it outputs 15. I thought that an array was a pointer, so the size of string2 should be the same as string1 right? So why is it that it prints out two different sizes for the same type of data (pointer)?

Answer 1

Arrays are not pointers. Array names decay to pointers to the first element of the array in certain situations: when you pass it to a function, when you assign it to a pointer, etc. But otherwise arrays are arrays - they exist on the stack, have compile-time sizes that can be determined with sizeof, and all that other good stuff.