Question

Im trying to write a function named ComputeMaximum that has two parameters, both of type pointer to constant double, and returns type pointer to double

I keep getting the following casting errors:

1. invalid conversion from ‘const double*’ to ‘double*’
2. cannot convert ‘double’ to ‘const double*’ for argument ‘1’ to ‘double* ComputeMaximum(const double*, const double*)’

#include <iostream>
using namespace std;

double *ComputeMaximum(const double *num1, const double *num2)
{
    return ((double*)num1>num2?num1:num2);  
}

int main()
{
    double *max;

    max = ComputeMaximum(6.4, 6.9);
    cout << *max;

    return 0;
}

Answer 1

if he actually wants to pass pointers and return a pointer (can’t think why unless this is homework) If you want const double you will need to put const before every use of the word double in this entire clip

#include <iostream>
using namespace std;

double *ComputeMaximum(double *num1,double *num2)
{
    return (* num1 > * num2 ?num1:num2);  // need to dereference the comparison
}

int main()
{
    double *max;
    double a = 6.4;
    double b = 6.9; // need to be variables with real adresses, literals won't work

    max = ComputeMaximum(&a, &b); // pass pointers to a and b
    cout << *max;

    return 0;
}