Substring in C#

CsharpProgrammingServer Side Programming

Substring is used to get the sub-parts of a string in C#. We have the substring() method for this purpose. Use the substring() method in C# to check each and every substring for unique characters. Loop it until the length of the string.

If anyone the substring matches another, then it would mean that the string does not have unique characters.

You can try to run the following code to determine if a string has all unique characters. The example shows the usage of Substring() method −


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

public class Demo {

   public bool CheckUnique(string str) {
      string one = "";
      string two = "";

      for (int i = 0; i < str.Length; i++) {
         one = str.Substring(i, 1);
         for (int j = 0; j < str.Length; j++) {
            two = str.Substring(j, 1);
            if ((one == two) && (i != j))
            return false;
      return true;

   static void Main(string[] args) {
      Demo d = new Demo();
      bool b = d.CheckUnique("amit");

Published on 13-Aug-2018 10:54:49