using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter a string");

        string temp = Console.ReadLine();

        string d= temp;

        Console.WriteLine("Enter a string to check 'Contains()' operation");

        Console.Write("String: ");

        string temp2= Console.ReadLine();

        Console.WriteLine();

        Console.WriteLine("Operation: string.Conatins()");

        Console.WriteLine("Original String: {0}", d);

        Console.WriteLine("Output: {0}",temp.Contains(temp2));

        Console.WriteLine();

        Console.WriteLine("Enter a string and index to check 'Insert()'operation");

        Console.Write("String: ");

        temp2 = Console.ReadLine();

        Console.Write("Index: ");

        int i = int.Parse(Console.ReadLine());

        Console.WriteLine();

        Console.WriteLine("Operation: string.Insert()");

        Console.WriteLine("Original String: {0}", d);

        Console.WriteLine("Output: {0}", temp.Insert(i,temp2));

        Console.WriteLine();

        Console.WriteLine("Enter a index to check 'Remove()' operation");

        Console.Write("Index: ");

        i = int.Parse(Console.ReadLine());

        Console.WriteLine();

        Console.WriteLine("Operation: string.Remove()");

        Console.WriteLine("Original String: {0}", d);

        Console.WriteLine("Output: {0}", temp.Remove(i));

        Console.WriteLine();

        Console.WriteLine("Enter a strings to check 'Replace()' operation");

        Console.Write("string to be replaced: ");

        string temp3= Console.ReadLine();

        Console.Write("string to replaced with: ");

        string temp4 = Console.ReadLine();

        Console.WriteLine();

        Console.WriteLine("Operation: string.Replace()");

        Console.WriteLine("Original String: {0}", d);

        Console.WriteLine("Output: {0}", temp.Replace(temp3,temp4));

        Console.WriteLine();

        Console.WriteLine("Original string is used to check 'ToUpper()' operation");

        Console.WriteLine();

        Console.WriteLine("Operation: string.ToUpper()");

        Console.WriteLine("Original String: {0}", d);

        Console.WriteLine("Output: {0}", temp.ToUpper());

        Console.ReadLine();

}

}

​