GCD

Prime b

So I am have been thinking how to make a program that will prompt a user for how many numbers he wants to find GCD from
Then it will list all the possible numbers for each number
And in the end it will show the GCD of the numbers either its 2 or 3 or 10 numbers

How would I do that?

4 Replies

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Prime b14y ago
Yeah it works just as it should.
Vulpes14y ago
No, for once, I sat down and did it properly :)

It worked fine when I compiled and ran it and I haven't used any fancy features so it should work on any version of C#.

Just copied and pasted it back into the compiler to make sure there was no pasting error and it's still working fine.

What errors are you getting?
Prime b14y ago
Vulpes did you do this on top of your head? Because it just has too many errors and wont compile
Vulpes14y ago
This code will get the GCD of any number of integers:

using System;

class GCD
{
static void Main()
{
int GCD1 = GetGCD(8, 12);
Console.WriteLine(GCD1); // 4
int GCD2 = GetGCD(15, 120, 45);
Console.WriteLine(GCD2); // 15
int GCD3 = GetGCD(7, 14, 49, 63, 70, 343, 21, 35, 77, 98);
Console.WriteLine(GCD3); // 7
Console.ReadKey();
}

static int GetGCD(params int[] numbers)
{
// get the smallest number as the GCD can't be larger than that
Array.Sort(numbers);
int min = numbers[0];
if (min < 1) throw new ArgumentException("The array can't include a number less than 1");
if (min == 1) return 1; // GCD must be 1

for(int i = min; i >= 1; i--)
{
int rem = min % i;
if (rem > 0) continue; // 'i' can't be a factor of min

bool isFactor = true;

for(int j = 1; j < numbers.Length; j++)
{
int rem2 = numbers[j] % i;
if (rem2 > 0) // 'i' can't be a factor of numbers[j]
{
isFactor = false;
break;
}
}

if (isFactor) return i; // 'i' must be the GCD
}

return 1; // needed to keep compiler happy, but will never get to this line
}
}