COMPARE STRINGS IN C#

Today in Engineer's World, we are discussing a very important topic of C# -String in very easy way. Posted By- +Manish Kumar Gautam +LIV WIRE  +ASP.NET SOLUTIONS

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To read STRING COMPARISON IN C# PART2 - Click here.

COMPARE STRING

Method5: Using string1.CompareTo(string2) method

Compare.To() method is an instance of a specified string or object. This method compares the instance of the specified string/object with the string/object that appears within the overload of the method as parameter. This method performs a case-sensitive comparison. It returns the output in Integer type.


Range(R)                 Description
outputValue<=0,   Means string1 less than string2.
outputValue=0,     Means string1 is equal as string2.
outputValue>=0,   Means string1 greater than string2. 

Let's see every Range(R) value cases-

R1: When string1 less than string2.Let's see this in action quickly

            string str1 = "A"; //ASCII Value for A=65
            string str2 = "B"; //ASCII Value for B=66
           
            int resp= str1.CompareTo(str2);
            Console.WriteLine("Response = {0}", resp);

Output: Response = -1.
The output is very straight forward as we can predict 65<66, which give as -1. 

R2: When string1 is equal as string2. 
Let's see this in action quickly

            string str1 = "A"; //ASCII Value for A=65
            string str2 = "A"; //ASCII Value for A=65
           
            int resp= str1.CompareTo(str2);
            Console.WriteLine("Response = {0}", resp);

Output: Response = 0.
The output is very straight forward as we can predict 65=65, which give as 0.

R3: When string1 greater than string2.Let's see this in action quickly

            string str1 = "B"; //ASCII Value for A=66
            string str2 = "A"; //ASCII Value for B=65
           
            int resp= str1.CompareTo(str2);
            Console.WriteLine("Response = {0}", resp);

Output: Response = 1.
The output is very straight forward as we can predict 66>65, which give as 1.

This method has two overloaded constructors.

Overload Method1: 

One takes two parameters(P) i.e. 
P1: string1(first specified string)
P2: string2(second specified string, compare instance with string1)

Let's do it practically when we pass the instance type string.


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Practical Implementation:

using System;

namespace AspnetSolutions

{
    class stringComparison
    {
        public static void Main()
         {
            string str1 = "B"; //ASCII Value for A=66
            string str2 = "A"; //ASCII Value for A=65

            int resp= str1.CompareTo(str2);
            Console.WriteLine("Response = {0}", resp);
        }
    }
}

Output

Hence, we get the response as expected from the first overload of CompareTo() method.

Overload Method2: 

One takes two parameters(P) i.e. 
P1: object1(first specified object)
P2: object2(second specified object, compare instance with object1)

Let's do it practically when we pass the instance type object (i.e. datetime, int, char, float, string anything).


Practical Implementation:
using System;

namespace AspnetSolutions

{
    class stringComparison
    {
        public static void Main()
        {
            //date passed in object
            DateTime date1=new DateTime(2015,7,5);
            DateTime date2=new DateTime(2000,7,5);
            int responseDate= date1.CompareTo(date2) ;
            Console.WriteLine("responseDate = {0}",responseDate);

            //Integer passed in object
            int number1 = 2523;
            int number2 = 5000;
            int responseInteger=number1.CompareTo(number2);
            Console.WriteLine("responseInteger = {0}", responseInteger);

            //character passed in object
            char ch1='a';
            char ch2 = 'z';
            int responseChar=ch1.CompareTo(ch2);
            Console.WriteLine("responseChar = {0}", responseChar);

            //string passed
            string str1 = "Hello";
            string str2 = "Programmers's";
            int resp= str1.CompareTo(str2);
            Console.WriteLine("Response = {0}", resp);
        }
    }
}

Output
All are working fine as you can see the output.

ResponseDate (+1) shows date1 is greater than date2.
ResponseInteger (-1) shows number1 is less than number2.
ResponseCharacter (-25) shows ch1 is less than ch2 by 25 characters. As ASCII of z-a=122-97=25.
ResponseString (-1) shows str1 is smaller than str2.

To read STRING COMPARISON IN C# PART3 - Click here.

Related Questions:

#newtoprgm try first program

Q-1 Can we apply ignorecase to CompareTo() method?
Ans- No.

Q-2 What will be the output of the code?

using System;

namespace AspnetSolutions
{
    class stringComparison
    {
        public static void Main()
        {
            string str1 = "a";
            string str2 = "A";

            int resp= str1.CompareTo(str2);
            Console.WriteLine("Response = {0}", resp);

        }
    }
}

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A) Response = 32
B) Response = -32
C) Response = -1
D) Response = 1

Ans- Option(C).

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