CODEWITHSUNDEEP
c#
Keegan Hart
Keegan Hart

Reputation: 23

Weighted Sum of Digits

I am trying to find the weighted sum of digits for example if I have 124 I need to make it: 1 * 1 + 2 * 2 + 4 * 3.

So far I have been able to multiply the numbers using a for loop like so:

Console.WriteLine("Input a number");
int num = Convert.ToInt32(Console.ReadLine());
int digit = 0;

for (int i = 4; i > 0; i--)
{                
    digit = num % 10 * i;
    num /= 10;
    Console.WriteLine(digit);
}

But I'm unsure as to how to add the numbers after.

Upvotes: 0

Views: 1216

Answers (4)

Dmitrii Bychenko
Dmitrii Bychenko

Reputation: 186668

If you are for simple solution (which is not very fast) you can try Linq:

Console.WriteLine("Input a number");
int num = Convert.ToInt32(Console.ReadLine());

Console.WriteLine(string.Join(" + ", num
  .Select((c, i) => $"{c - '0'} * {i + 1}")););

Outcome:

1 * 1 + 2 * 2 + 4 * 3

If you want to find out the sum, add Sum:

int sum = num
  .Select((c, i) => (c - '0') * (i + 1))
  .Sum();

Upvotes: 0

Sagar Shinde
Sagar Shinde

Reputation: 160

  int num, sum = 0, r;
        Console.WriteLine("Enter a Number : ");
        num = int.Parse(Console.ReadLine());          
       var add_n=(num.ToString().Length)+1;
        while (num != 0)
        {

            r = num % 10;
            num = num / 10;
            //Console.WriteLine(r+" "+(add_n-1));
            sum = sum + (r*(add_n-1));
            add_n--;
        }
        Console.WriteLine("Sum of Digits of the Number : "+sum);
        Console.ReadLine();

Upvotes: 0

Chetan Mehra
Chetan Mehra

Reputation: 199

Are you trying to achieve this?

Console.WriteLine("Input a number");
int num = Convert.ToInt32(Console.ReadLine());
int digit = 0;
int i=num.ToString().Length;
int Sum= 0;
int digit2=0;
while(num>0)
{
digit= num%10;
digit2=digit*i;
Sum=Sum+digit2;
num=num/10;
i--;
}
Console.Writeline(Sum);

Upvotes: 1

Milad Aghamohammadi
Milad Aghamohammadi

Reputation: 1976

you can do this for 4 digits numbers

Console.WriteLine("Input a number");
int num = Convert.ToInt32(Console.ReadLine());
int sum = 0;

for (int i = 4; i > 0; i--)
{                
    sum += num % 10 * i;
    num /= 10;
}

Console.WriteLine(sum);

but if you want your code work for any number, do this

Console.WriteLine("Input a number");
int num = Convert.ToInt32(Console.ReadLine());
int sum = 0;

for (int i = num.ToString().Length; i > 0; i--)
{                
    sum += num % 10 * i;
    num /= 10;
}

Console.WriteLine(sum);

Upvotes: 1

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