C ++函数和指针

Question

I have an assignment to write a small program that includes using pointers and functions to find square root. I'm getting an error that says "none of the 3 overloads could convert all the argument types" thanks for the help in advance

here is the code i have so far. I know it's a mess, I hope you guys can help.

void SqrRt(unsigned long int *, unsigned long int *);

int main() {

    unsigned long int number, root;

    cout << "Type in any number greater than 0 to find it's square root: ";
    cin >> number;

    SqrRt(&number, &root);

    return 0;
}

void SqrRt(unsigned long int *num, unsigned long int *rt){

    if (num >= 0)
        rt = sqrt(num);
    else
        cout << "Invalid input! Number should be greater than 0!";
    }

Answer 1

sqrt can handle only numbers, not pointers to them , so everything you'll have to do is to dereference a pointer you're passing to sqrt .

What's more, sqrt returns a number as well, so you should also dereference the pointer you're assigning to.

Answer 2

You need to rewrite rt = sqrt(num) to *rt = sqrt(*num) . The problem with your code is that you are not referring to the underlying object ie, the object the pointer points to. I would suggest you to, if possible to use references as it is much easier to work with as compared to pointers.