Pointer dereferencing

Question

char *m_chString="asd"; 
cout<<m_chString;//prints asd
cout<<*m_chString;//prints a


int nValue = 7;
int *pnPtr = &nValue;
cout<<*pnPtr;//prints 7
cout<<pnPtr;//prints the address of nValue

I gave two examples, in the first the pointer points to a string, and in the second, the pointer prints to an int value.
My question is, why cout<<m_chString; from the first example doesn't print the address of my string as it would do in the second example if I were to print pnPtr without dereferencing it?
Doesn't pnPtr point to an address?

I'm not trying to print its address, I am trying to understand why it behaves like that. — George Irimiciuc, Oct 28 '14 at 08:19

ravi · Accepted Answer · 2014-10-28T08:24:10.023

2

The reason for that is that std::cout will treat a char * as a pointer to (the first character of) a C-style string and print it as such.

You can print the address by:-

    cout << (void *) m_chString;

OR if you are great C++ fan then

    cout << static_cast <const void *> (m_chString);

edited Oct 28 '14 at 08:24

answered Oct 28 '14 at 08:17

ravi

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+1 since the general idea is right, but you might want to clarify that it's not `std::cout` itself doing this. It's the overload of `operator< – Angew is no longer proud of SO Oct 28 '14 at 08:22
If it points to the first character, then why doesn't it print only that one and it prints the whole string? – George Irimiciuc Oct 28 '14 at 08:22
@Angew yes agree with you. – ravi Oct 28 '14 at 08:25
@GeorgeIrimiciuc Please see Angew's explanation. – ravi Oct 28 '14 at 08:26
@GeorgeIrimiciuc Because whoever designed the streams library decided it was more useful to treat `char*` as a pointer to a null-terminated string and print the whole string. – juanchopanza Oct 28 '14 at 08:26
@GeorgeIrimiciuc Bracketing in the sentence. It treats it as a pointer to the first character of (a C-style string and prints it as such). Simply put: it's designed for printing strings. – Angew is no longer proud of SO Oct 28 '14 at 08:26
I see. The thing is if I do `cout< – George Irimiciuc Oct 28 '14 at 08:28
@GeorgeIrimiciuc: With `cout< – Benjamin Lindley Oct 28 '14 at 08:32
Ah, you're right. Thanks. – George Irimiciuc Oct 28 '14 at 08:32

Pointer dereferencing

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