## Monthly Archives: March 2022

## C# || How To Compare Version Numbers Using C#

The following is a module with functions which demonstrates how to compare version numbers using C#.

1. Compare Version – Problem Statement

Given two version numbers, **version1** and **version2**, compare them.

Version numbers consist of **one or more revisions** joined by a dot **‘.’**. Each revision consists of **digits** and may contain leading **zeros**. Every revision contains **at least one character**. Revisions are **0-indexed from left to right**, with the leftmost revision being revision 0, the next revision being revision 1, and so on. For example **2.5.33** and **0.1** are valid version numbers.

To compare version numbers, compare their revisions in **left-to-right order**. Revisions are compared using their **integer value ignoring any leading zeros**. This means that revisions **1** and **001** are considered **equal**. If a version number does not specify a revision at an index, then **treat the revision as 0**. For example, version

**1.0**is less than version

**1.1**because their revision 0s are the same, but their revision 1s are

**0**and

**1**respectively, and

**0 < 1**.

*Return the following:*

- If
**version1 < version2**, return**-1**. - If
**version1 > version2**, return**1**. - Otherwise, return
**0**.

**Example 1:**

Input:version1 = "1.01", version2 = "1.001"

Output:0

Explanation:Ignoring leading zeroes, both "01" and "001" represent the same integer "1".

**Example 2:**

Input:version1 = "1.0", version2 = "1.0.0"

Output:0

Explanation:version1 does not specify revision 2, which means it is treated as "0".

**Example 3:**

Input:version1 = "0.1", version2 = "1.1"

Output:-1

Explanation:version1's revision 0 is "0", while version2's revision 0 is "1". 0 < 1, so version1 < version2.

2. Compare Version – Solution

The following is a solution which demonstrates how to compare version numbers.

```
```
12345678910111213141516171819202122232425
// ============================================================================// Author: Kenneth Perkins// Date: Mar 1, 2022// Taken From: http://programmingnotes.org/// File: Solution.cs// Description: Demonstrates how to compare version numbers// ============================================================================public class Solution { public int CompareVersion(string version1, string version2) { var revisions1 = version1.Split("."); var revisions2 = version2.Split("."); var length = Math.Max(revisions1.Length, revisions2.Length); for (int index = 0; index < length; ++index) { var v1 = index < revisions1.Length ? int.Parse(revisions1[index]) : 0; var v2 = index < revisions2.Length ? int.Parse(revisions2[index]) : 0; if (v1 < v2) { return -1; } else if (v1 > v2) { return 1; } } return 0; }}// http://programmingnotes.org/

**QUICK NOTES**:

The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output for the example cases:

0

0

-1