Elysian Shadows

avansc wrote:jeez, i must be more nerdy than i thought.

public class Addition {
	public static void main(String[] args) {
		java.util.Scanner input = new java.util.Scanner(System.in);
		System.out.print("Enter first number: ");
		int p = input.nextInt();
		System.out.print("Enter second number: ");
		int q = input.nextInt();
		System.out.println("Carries of " + p + " + " + q +
				" = " + numberCarries(p, q, 0));
	}

	public static int numberCarries(int p, int q, int n) {
		if ((p + q) < 10) {
			return n;
		} else {
			if ( ((p % 10) + (q % 10)) < 10)
				return numberCarries(p / 10, q / 10, n);
			else
				return numberCarries((11 + p) / 10, q / 10, n + 1);
		}
	}
}

avansc wrote:i'll post some hints. some things i used.
i used mod, with base 10. "num%10= remainer" - this is how you isolate the last digit in the number like 1234%10=4
i have 2 if statements.
and i use recursion.

armed with that you should probably come to the same function as me. its only about 6-7 lines in length

public class Addition {
	public static void main(String[] args) {
		java.util.Scanner input = new java.util.Scanner(System.in);
		System.out.print("Enter first number: ");
		int p = input.nextInt();
		System.out.print("Enter second number: ");
		int q = input.nextInt();
		System.out.println("Carries of " + p + " + " + q +
				" = " + numberCarries(p, q, 0));
	}

	public static int numberCarries(int p, int q, int n) {
		if ((p + q) < 10)
			return n;
		else
			return ( ((p % 10) + (q % 10)) < 10) ? numberCarries(p / 10, q / 10, n) : numberCarries((11 + p) / 10, q / 10, n + 1);
	}
}

Kleithap wrote:

avansc wrote:jeez, i must be more nerdy than i thought.

Heh, don't worry about it.

Here's a simple Java class that solves the problem:

Code: Select all

public class Addition {
	public static void main(String[] args) {
		java.util.Scanner input = new java.util.Scanner(System.in);
		System.out.print("Enter first number: ");
		int p = input.nextInt();
		System.out.print("Enter second number: ");
		int q = input.nextInt();
		System.out.println("Carries of " + p + " + " + q +
				" = " + numberCarries(p, q, 0));
	}

	public static int numberCarries(int p, int q, int n) {
		if ((p + q) < 10) {
			return n;
		} else {
			if ( ((p % 10) + (q % 10)) < 10)
				return numberCarries(p / 10, q / 10, n);
			else
				return numberCarries((11 + p) / 10, q / 10, n + 1);
		}
	}
}

public static int numberCarries(int p, int q) {
      if ((p + q) < 10) {
         return 0;
      } else {
         if ( ((p % 10) + (q % 10)) < 10)
            return 0 + numberCarries(p / 10, q / 10, n);
         else
            return 1 + numberCarries((11 + p) / 10, q / 10);
      }
   }

Kleithap wrote:

avansc wrote:i'll post some hints. some things i used.
i used mod, with base 10. "num%10= remainer" - this is how you isolate the last digit in the number like 1234%10=4
i have 2 if statements.
and i use recursion.

armed with that you should probably come to the same function as me. its only about 6-7 lines in length

Well, yeah that's exactly what I did. If you want to make the function shorter you can always do this:

Code: Select all

public class Addition {
	public static void main(String[] args) {
		java.util.Scanner input = new java.util.Scanner(System.in);
		System.out.print("Enter first number: ");
		int p = input.nextInt();
		System.out.print("Enter second number: ");
		int q = input.nextInt();
		System.out.println("Carries of " + p + " + " + q +
				" = " + numberCarries(p, q, 0));
	}

	public static int numberCarries(int p, int q, int n) {
		if ((p + q) < 10)
			return n;
		else
			return ( ((p % 10) + (q % 10)) < 10) ? numberCarries(p / 10, q / 10, n) : numberCarries((11 + p) / 10, q / 10, n + 1);
	}
}

avansc wrote:your code does not work, it produces 2 carries for the numbers 1901 and 99, it should be 3.

public static int numberCarries(int p, int q, int carry) {
      if ((p + q) + carry < 10)
         return 0;
      else
         return ( ((p % 10) + (q % 10) + carry) < 10) ? 0 + numberCarries(p / 10, q / 10, 0) : 1 + numberCarries(p / 10, q / 10, 1);
 }

avansc wrote:this little challange is trickier than you might think. and illustrates why you should allways test your code.

Kleithap wrote:

avansc wrote:your code does not work, it produces 2 carries for the numbers 1901 and 99, it should be 3.

Oops, you're right.

I've quickly made a simple one that uses an actual carry flag :D

Code: Select all

public static int numberCarries(int p, int q, int carry) {
      if ((p + q) + carry < 10)
         return 0;
      else
         return ( ((p % 10) + (q % 10) + carry) < 10) ? 0 + numberCarries(p / 10, q / 10, 0) : 1 + numberCarries(p / 10, q / 10, 1);
 }

It can probably be made more efficient but I don't have any time right now and I couldn't leave you without a solution . I didn't really have time to test this one, if you find any other bugs be sure to let me know. If I have time I'll look for a better solution tomorrow.

avansc wrote:this little challange is trickier than you might think. and illustrates why you should allways test your code.

I'm always happy when my sloppiness can be of use to other people.

avansc wrote:hahah, thats almost verbatim what i had.

Kleithap wrote:

avansc wrote:hahah, thats almost verbatim what i had.

Haha, great minds think alike :P

Seriously though, let everybody know when you think of another challenge, this one was pretty cool!

avansc wrote:hahah, thats almost verbatim what i had. nice work. unless someone gets something better you have yourself a copy of VS2008