char * and char[]

Question

Why is this right ?

#include<iostream>
using namespace std;
int main()
{
    char *s="raman";
    char *t="rawan";
    s=t;
    cout<<s;

return 0;
}

But this is wrong?

#include<iostream>
using namespace std;
int main()
{
    char s[]="raman";
    char t[]="rawan";
    s=t;
    cout<<s;

return 0;
}

Answer 1

In the first example, s=t does a pointer assignment. In the second, s=t tries to assign a pointer value (resulting from the implicit conversion, or "decay", of the array expression t) to an array object. C++ doesn't permit array assignments.

C and C++ happen to be very similar in this area; section 6 of the comp.lang.c FAQ covers the relationship between arrays and pointers very well.

Answer 2

The first example assigns an pointer to another which is valid.

The second example assigns an array to another array which in not allowed in C & C++ both.

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This excellent C++ FAQ entry and this answer should be a good read for you.