Newbie "new" nuisance

I'm currently going through a C++ primer and one of the exercises was to create storage of various types using "new," to print the addresses and then delete them. Here is my code:

Code:

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#include <iostream>
using namespace std;

int main()
{
        int* i = new int;
        long* l = new long;
        char* c = new char;
        float* f = new float[100];

        cout << "Address of i: " << i << endl;
        cout << "Address of l: " << l << endl;
        cout << "Address of c: " << c << endl;
        cout << "Address of f: " << f << endl;

        delete i;
        delete l;
        delete c;
        delete f;

        getchar();
        return 0;
}

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It prints the address fine except for the pointer to char. This is what I get:

Code:

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Address of i: 007D4B50
Address of l: 007D4B90
Address of c: ═²²²²½½½½½½½½■ε■
Address of f: 007D4C10

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How come the char* is printing as garbage?

When printing a char pointer, cout tries to print a string (null terminated array of characters starting at the address given). This is different behavior than in the other cases. Try this:

Code:

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cout << "Address of c: " <<  reinterpret_cast<void*>(c) << endl;

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Code:

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float* f = new float[100];

...

delete f;

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That last bit needs to be delete [] f since you've allocated an array of elements and not just a single one.

Aha! That all makes sense and thanks for reminding me about the delete []f.

However - do I have to use a "reinterpret_cast"? It works OK with a simple (void*) cast too.

Quote:

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Originally Posted by Sharke

However - do I have to use a "reinterpret_cast"? It works OK with a simple (void*) cast too.

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You should use reinterpret_cast as it is easier to spot, more ugly, and the C++ style casts document your intentions better.