Did I do this right? Function returning two reference parameters

[potato4610]

* I meant pointer parameters

This function that has two parameters, both of type reference and return reference to pointer.
Do I need to fix anything?
I have been stumped for days and dunno what I should fix

here is my code:

#include <iostream>
using namespace std;

double *ComputeMaximum( const double *num1a, const double *num2a);

int main() 
{
    double num1;
    double num2;
    cout << "Please enter two numbers: ";
    cin >> num1 >> num2;
    cout << "The greatest value is: " << ComputeMaximum(num1, num2) << " and its pointer is: " << *ComputeMaximum(num1, num2);
    return 0;
}

double *ComputeMaximum( const double *num1a, const double *num2a)
{
    return (double *)(num1a > num2a ? num1a : num2a);
}

[arkoenig]

Line 16 compares the values of the two pointers, not the values of the doubles to which they point.

Also, if your argument is const double *, that means you're promising not to change the value to which the pointer points. If you now return double *, you're violating that promise.

Fix these two problems and your ComputeMaximum function looks like this:

const double *ComputeMaximum(const double *num1a, const double *num2a)
{
    return *num1a > *num2a? num1a: num2a;
}

Because you are expecting pointers rather than references, you need to pass the addresses of the numbers in line 12. Also, you have swapped value and address:

cout << "The greatest value is: " << *ComputeMaximum(&num1, &num2) << " and its pointer is: " << ComputeMaximum(&num1, &num2);

And, of course, you need to change line 4 to match the function:

const double *ComputeMaximum(const double *num1a, const double *num2a);

[potato4610]

the output for my references was this:

Please enter two numbers: 1 4
The greatest value is: 4 and its address is: 0x7fff5fbff7b0

when I did what you edited, (thanks so much by the way), my output was:

Please enter two numbers: 1 4
The greatest value is: 4 and its pointer is: 0x7fff5fbff7b0

Does that sound about right?

[dusktreader]

You could do this in an even cleaner fashion by using references. If you use const references, you can pass in values that have not been saved in a variable:

#include <iostream>
#include <vector>

using namespace std;

const double& max( const double& a, const double& b )
{
    return a > b ? a : b;
}

int main()
{
    cout << max( 5.0, 7.0 ) << endl;
    double a = 13.0;
    double b = 11.0;
    double c = max( a, b );
    cout << c << endl;
    return 0;
}