Basic Number Theory Test

[ldelsignore]

Hello. I am trying to write a program for class where the user inputs two numbers (non-negative) and determines whether their product is within 2 of a multiple of ten. I am now trying to figure out how to determine whether the product is within a multiple of ten. I have figured that I need to test whether x * y equals a certain number (z), but I am not sure what qualities I should assign to z. I have tried using something like... if (z%10 == 0) ...then I would use that value of z to determine if the product is a multiple of 10. I would really appreciate some help with this problem. Thanks.

 #include <iostream>
using namespace std;
int main()
{
    int x, y, z;
    cout << "Enter the first number.\n";
    cin >> x;
    cout << "Enter the second number.\n";
// I am not sure what to put on the new line or if I am even taking the right path on this at all.
    z = 
    if (x * y == z)
    return 0;
}

[Duthomhas]

What do you mean by "within 2 of a multiple of ten"? As in, if

    xy = 10k ± 2

It will help you to remember that while % is called the "modulo" operator, but it would be more correct to call it the remainder operator.

That's a major hint right there.


One other thing: in C and C++, % is not defined over negative values. Make sure that you compute |xy|.

Good luck!