C# String Compare()

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      string str1 = "C#";
      string str2 = "Programiz";

      // compares str1 with str2
      // returns -1 because C# comes before Programiz in alphabetical order
      int result = String.Compare(str1, str2);
      Console.WriteLine(result);

      Console.ReadLine();
    }
  } 
}

// Output: -1

Compare() Syntax

The syntax of the string Compare() method is:

String.Compare(string str1, string str2)

Here, Compare() is a method of class String.

Compare() Parameters

The Compare() method takes the following parameters:

• str1 - first string for comparison
• str2 - second string for comparison

Compare() Return Value

The Compare() method returns:

• 0 - if the strings are equal
• positive integer - if the first string comes after the second string in the alphabetical order
• negative integer - if the first string comes before the second string in the alphabetical order

Example 1: C# String Compare()

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      string str1 = "C#";
      string str2 = "C#";
      string str3 = "Programiz";

      int result;
       
      // compares str1 with str2
      result = String.Compare(str1, str2);
      Console.WriteLine(result);

      //compares str1 with str3
      result = String.Compare(str1, str3);
      Console.WriteLine(result);

      //compares str3 with str1
      result = String.Compare(str3, str1);
      Console.WriteLine(result);
      
      Console.ReadLine();
    }
  } 
}

Output

0
-1
1

Here,

• String.Compare(str1, str2) returns 0 since str1 and str2 are equal
• String.Compare(str1, str3) returns -1 since str1 comes before str3
• String.Compare(str3, str1) returns 1 since str3 comes after str1

Example 2: Check if Two Strings Are Equal

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      string str1 = "C#";
      string str2 = "C#";
      
      // if str1 and str2 are equal, the result is 0
      if(String.Compare(str1, str2) == 0)
 {

        Console.WriteLine("str1 and str2 are equal");
      }

      else {
        Console.WriteLine("str1 and str2 are not equal.");
      }

      Console.ReadLine();
    }
  } 
}

Output

str1 and str2 are equal

Since, str1 is equal to str2, String.Compare(str1, str2) returns 0.

Example 3: C# String Compare() With Case

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      string str1 = "Programiz";
      string str2 = "programiz";

      int result;
      
      // compares str1 and str2
      result = String.Compare(str1, str2);
      Console.WriteLine(result);

      Console.ReadLine();
    }
  } 
}

Output

1

When "Programiz" is compared to "programiz", we do not get 0. It is because the Compare() method considers the letter case.

Example 4: C# String Compare() - Ignore Case

using System;  
namespace CsharpString {  
  class Test {
    public static void Main(string [] args) {

      string str1 = "Programiz";
      string str2 = "programiz";

      int result;
      bool ignoreCase = true;

      // compares by ignoring case
      result = String.Compare(str1, str2, ignoreCase);
      Console.WriteLine(result);

      Console.ReadLine();
    }
  } 
}

Output

0

When "Programiz" is compared to "programiz", we get 0. This is because we have the Boolean value true in the method parameter, which ignores the case during string comparison.