Assigning an array to an address and printing values

Question

I need to do the following:

Assume that the C++ array

int fib[] = { 0, 1, 1, 2, 3, 5, 8, 13, 21 };

is stored on a 32-bit machine, at memory address 0xA0000000 (hexadecimal). What are the values of the following expressions?

  fib     
  *fib     
  &fib[0]     
  &fib[6]     
  *(fib+7)

I tried writing this code to try and print out the desired values.

int main()
{
    int i = 0;
    int *p = &A0000000;
    cout << "i= " << i << endl;
    cout << "p= " << p << endl;
    *p = 0;
    cout << "i=" << i << endl;

    int &r = i;
    r = 0;
    cout << "i= " << i << endl;


    int fib[] = { 0, 1, 1, 2, 3, 5, 8, 13, 21 };
    cout << "fib= " << fib << endl;

    cout << "*(*fib)= "  << *fib     <<  endl;
    cout << "&fib[0]= "  << &fib[0]  <<  endl;
    cout << "*(fib+7)= " << *(fib+7) <<  endl;
    cout << "&fib[6]= "  << &fib[6]  <<  endl;

    system("PAUSE");
    return 0;
} 

I get the following error message:

c:\users\inquirer\documents\visual studio 2010\projects\fib1\fib1\fib1.cpp(7): error C2065: 'A0000000' : undeclared identifier

Thank you in advance for the help. What do I need to do to print out the correct values?

Answer 1

To fix the compilation error try

int* p=(int*)0xA0000000;

Whatever this should be good for ...

Answer 2

You cannot store something at an arbitrary virtual memory address.

*p = 0; will crash at runtime, because 0xa0000000 is probably not a valid location to write to.

Try int *p = new int and print the address you got. It will be less beautiful than 0xa0000000 but it will be sufficient to visuallise your experiment.