C#: Replace lowercase characters by uppercase and vice-versa

C# Sharp String: Exercise-15 with Solution

Write a C# Sharp program to read a sentence and replace lowercase characters with uppercase and vice-versa.

Sample Solution:-

C# Sharp Code:

using System;

// Define the exercise15 class
public class exercise15
{
    // Main method - entry point of the program
    public static void Main()
    {
        string str1; // Declare a string variable to store input
        char[] arr1; // Declare a character array variable
        int l, i; // Declare integer variables
        l = 0; // Initialize variable 'l' to 0
        char ch; // Declare a character variable 'ch'

        // Prompt the user for input
        Console.Write("\n\nReplace lowercase characters by uppercase and vice-versa :\n");
        Console.Write("--------------------------------------------------------------\n");
        Console.Write("Input the string : ");
        str1 = Console.ReadLine(); // Read the input string from the user
        l = str1.Length; // Get the length of the input string
        arr1 = str1.ToCharArray(0, l); // Convert the string into a character array

        Console.Write("\nAfter conversion, the string is : ");

        // Loop through each character in the array
        for (i = 0; i < l; i++)
        {
            ch = arr1[i]; // Get the current character

            // Check whether the character is lowercase
            if (Char.IsLower(ch))
            {
                Console.Write(Char.ToUpper(ch)); // Convert lowercase character to uppercase and print
            }
            else
            {
                Console.Write(Char.ToLower(ch)); // Convert uppercase character to lowercase and print
            }
        }
        Console.Write("\n\n");
    }
}

Sample Output:

Replace lowercase characters by uppercase and vice-versa :                                                    
--------------------------------------------------------------                                                
Input the string : w3RESOURCE                                                                                 
                                                                                                              
After conversion, the string is : W3resource 

Flowchart:

C# Sharp Code Editor:

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