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Archives for May 2020

Linear Search in C#

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Linear search is used for searching an item in a list of items,such as in Array.It is not efficient when compared to other ways of searching item in an array.
public static int LinearSearch(int[] A,int val)
{
for(int i=0;i<A.Length;i++)
{
if(A[i]==val)
return i;
}
return-1;
}
We can sort  items in the array before calling linear search function to improve performance
Array.Sort(vals);

Filed Under: C#

Find non repeating characters in a string using LINQ

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Commonly we need to find the characters in a string which are not repeated or which occurs only once.We can use the following LINQ example to find such characters.

Though this is a short string but you can see that even in this string all characters are repeated except M,L and O.

We first iterate through the string characters one at a time.Then we compare if the last index of that character is same as the first index.If that is the case then we return that element.


using System;
using System.Collections.Generic;
using System.Linq;

namespace LINQ
{
public class Program
{
public static void Main(string[] args)
{
string examplestring=”THIS IS A SIMPLE STRING TO TEST REPEATING CHARACRTERS”;
var chars=examplestring.Where(ch=>examplestring.IndexOf(ch)==examplestring.LastIndexOf(ch));
foreach(var ch in chars)
{
Console.WriteLine(ch);
}

}
}
}

Overview of Azure Functions

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Azure functions are used to isolated small pieces of logic.These functions are triggered when some triggering even happens.

  • Azure fucntions is a Serverless computing technology
  • Azure functions can be created using C#,Typescript and many different technologies
  • Azure functions are based on triggers,events and isolated code.
  • Events cause trigger to fire which causes the function to execute.

Some of the events or triggers which cause Function to execute are:

  • HTTP Request
  • Schedule
  • Blob storage
  • Queue storage
  • Event Grid
  • Event Hub
  • Service Bus Queue
  • Service Bus Topic

Azure functions is a type of App service.Other examples of App Services are Web App and Logic Apps.The benefit of Azure function is that since it is based on serverless architecture so you don’t need to be concerned with the lower level details of the functions such as mananging the OS and middleware.

This makes it easy not only to develop but also to deploy and scale the application.

Following is a basic function which is executed when http trigger is fired

import { AzureFunction, Context, HttpRequest } from “@azure/functions”
const httpTrigger: AzureFunction = async function (context: Context, req: HttpRequest): Promise<void> {
context.log(‘HTTP trigger function processed a request.’);
constname= (req.query.name|| (req.body&&req.body.name));
if (name) {
context.res= {
// status: 200, /* Defaults to 200 */
body: “Hello “+ (req.query.name||req.body.name)
};
}
else {
context.res= {
status: 400,
body: “Please pass a name on the query string or in the request body”
};
}
};
export default httpTrigger;

 

Check if a string is palindrome in C#

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Here we will be checking if a string is palindrome.To check if string is palindrome we need to know the occurrence of each character.Every character should occur even number of times.This is except the case when the length of the string is not even.So for example if the length of the string is 5 then except one all other characters should occur even number of times.

Check if a string is palindrome in csharp


using System;
using System.Collections.Generic;
namespace CSharpAlgos
{
class Program
{
static void Main(string[] args)
{
string name="abczcba";
bool pal=true;
//if the string contains even characters
if(name.Length%2==0)
{
//each character should occur even number of times
Dictionary<char,int> dic=newDictionary<char, int>();
foreach(var ch inname)
{
if(!dic.ContainsKey(ch))
dic.Add(ch,0);
dic[ch]=dic[ch]+1;

}
foreach(KeyValuePair<char,int> kv indic)
{
if(kv.Value%2!=0)
pal=false;
Console.Write(kv.Value);
}

}
else
{
int count=0;
//each character should occur even number of times
Dictionary<char,int> dic=newDictionary<char, int>();
foreach(var ch inname)
{
if(!dic.ContainsKey(ch))
dic.Add(ch,0);
dic[ch]=dic[ch]+1;

}
foreach(KeyValuePair<char,int> kv indic)
{
if(kv.Value%2!=0)
{
count++;
if(count==2)
pal=false;
}
Console.Write(kv.Value);
}

}
Console.WriteLine(pal);
}
}
}