CODEWITHSUNDEEP
c#
Doug Peters
Doug Peters

Reputation: 529

Attach decimal part to an integer

I need to be able to attach an integer number to another integer as a decimal part, for example:

For numbers 12345 and 12345678 I would want to get: 12345,12345678

Note: The numbers' length is variable.

I have tried casting numbers to string to measure their length and then divide them accordingly but there must be a more efficient and fast way than this.

Upvotes: 1

Views: 130

Answers (4)

Ulugbek Umirov
Ulugbek Umirov

Reputation: 12797

Based on https://stackoverflow.com/a/2506541/1803777, more performance can be obtained without usage of logarithm function.

public static decimal GetDivider(int i)
{
    if (i < 10) return 10m;
    if (i < 100) return 100m;
    if (i < 1000) return 1000m;
    if (i < 10000) return 10000m;
    if (i < 100000) return 100000m;
    if (i < 1000000) return 1000000m;
    if (i < 10000000) return 10000000m;
    if (i < 100000000) return 100000000m;
    if (i < 1000000000) return 1000000000m;
    throw new ArgumentOutOfRangeException();
}

int a = 12345;
int b = 12345678;
decimal x = a + b / GetDivider(b);

Upvotes: 2

Vlad
Vlad

Reputation: 377

try counting using the following:

Math.Floor(Math.Log10(n) + 1);

then continue just as you stated.

Source: How can I get a count of the total number of digits in a number?

Upvotes: 1

spender
spender

Reputation: 120450

var left = 12345;
var right = 12345678;
var total = left + (right / Math.Pow(10, Math.Floor(Math.Log10(right)) + 1));

Upvotes: 4

Code Uniquely
Code Uniquely

Reputation: 6373

A very quick and dirty approach, with no error checking at all

var total = Double.Parse(string.Concat(left, ",", right));

Upvotes: 3

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