char p[] and char* p

S1:

snip1:  char p[] = "abc";     *(p+1) = 'a';    

snip2:  char * p ="abc";     *(p+1) = 'a';

Snip2 will be compiling-warning. For the char pointer p points to a constant char array, and it change the constant string latter.

Snip1 will pass compiling successfully. For the "abc" is copied to the memory for char p[].

S2:

char str1[3],str2[3];

str1="ab";

str2=str1;//error!

strcpy(str2,str1);//right!

reason: the compiler see the operater "=" to be the "=" of pointer operation(invalid).