C# StringComparer.Compare() Method

In C#, the Compare method is used to compare two objects or strings and returns an indication of their relative sort order.

Example: C# program to illustrate how to use StringComparer() to perform ordinal comparison.

// C# program to illustrate the 
// CompareOrdinal(String, Int32, 
// String, Int32, Int32) method
using System;

class Geeks
{
	static public void Main()
	{

	string s1 = "GFG";
	string s2 = "GFG";

	int res = StringComparer.Ordinal.Compare(s1, s2);

	if (res < 0)
		Console.WriteLine($"{s1} is less than {s2}");
	
	else if (res > 0)
		Console.WriteLine($"{s1} is greater than {s2}");
	
	else
		Console.WriteLine($"{s1} is equal to {s2}");


	}
}

GFG is equal to GFG

Explanation: In this example, the StringComparer.Ordinal.Compare() method checks if two strings are equal. It returns 0 when both strings are identical, a negative value if the first string is less, and a positive value if it is greater.

Overloads of StringComparer.Compare() Method

There are 2 methods in the overload list of this method:

1. Compare(Object a, Object b)

This method compares two objects and returns an indication of their relative sort order when overridden in a derived class.

Syntax:

public int Compare (object a, object b);

• Parameters: This method takes two parameter, object a is the first object which has to be compared and the object b is the second object which has to be compared with the object a.
• Return Type: This method returns 0, if both the objects are equal also return positive number if object a is lexicographically greater than object b, also return negative number if the object a is lexicographically lesser than the object b.

Note: This method throws an ArgumentException if the objects being compared are not of the same type.

Example: In this example, we are comparing two objects using the StringComparer.Compare(Object, Object) method.

// Demonstrating the working of 
// StringComparer.Compare() method
using System;
class Geeks
{
    static void Main()
    {
        // Creating two objects holding string 
        // values "Geek" and "Geeks"
        object obj1 = "Geek";
        object obj2 = "Geeks";

        // Using StringComparer.Ordinal 
        // to compare the two string objects
        int result = StringComparer.Ordinal.Compare(obj1, obj2);

        // Checking the result of comparison and 
        // printing appropriate message
        if (result < 0)
            Console.WriteLine($"{obj1} is less than {obj2}");
        else if (result > 0)
            Console.WriteLine($"{obj1} is greater than {obj2}");
        else
            Console.WriteLine($"{obj1} is equal to {obj2}");
    }
}

Geek is less than Geeks

2. Compare(String a, String b)

This method compares two strings and returns an indication of their relative sort order when overridden in a derived class.

Syntax:

public abstract int Compare (string a, string b);

• Parameters: This method takes two paramter, string a is the first string which has to be compared and the string b is the second string which has to be compared with the string a.
• Return Type: This method returns zero if both the string objects are equal, it also returns a positive number if the string a is greater than string b, it also returns a negative number if the string a is lesser than the string b.

Note: This method throws an ArgumentException

Example: In this example, we are comparing two string objects using the StringComparer.Compare(String, String) method.

// Demonstrating the working of 
// Compare(String a, String b) method
using System;
class Geeks
{
    static void Main()
    {
        // Define two strings to compare
        string s1 = "geek";
        string s2 = "Geek";

        // Compare the two strings using 
        // ordinal (Unicode) comparison
        int result = StringComparer.Ordinal.Compare(s1, s2);

        // Print the comparison result
        // Positive number means s1 > s2, 
        // negative means s1 < s2, 
        // zero means equal
        Console.WriteLine(result);
    }
}

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