C#: Convert Octal number to Decimal number

C# Sharp For Loop: Exercise-51 with Solution

Write a program in C# Sharp to convert an octal number to decimal without using an array.

Visual Presentation:

Sample Solution:

C# Sharp Code:

using System;  // Importing necessary namespace

public class Exercise51  // Declaration of the Exercise51 class
{  
    public static void Main()  // Main method, entry point of the program
    {
        // Declaration of variables
        int n1, n5, p = 1, k, ch = 1;
        int dec = 0, i = 1, j, d;

        // Displaying information about converting octal to decimal
        Console.Write("\n\n");
        Console.Write("Convert Octal number to Decimal number:\n");
        Console.Write("------------------------------------------");
        Console.Write("\n\n");	

        // Prompting the user to enter an octal number
        Console.Write("Input an octal number (using digit 0 - 7) :");
        n1 = Convert.ToInt32(Console.ReadLine());  // Reading the octal number
        n5 = n1;  // Storing the original number for display

        // Loop to check if the entered number is a valid octal number
        for (; n1 > 0; n1 = n1 / 10)
        {
            k = n1 % 10;
            if (k >= 8) 
            { 
                ch = 0;  // If a digit is more than 7, it's not a valid octal number
            }
        }

        // Switch statement to handle validation and conversion
        switch (ch)
        {
            case 0:
                Console.Write("\nThe number is not an octal number. \n\n");
                break;
            case 1:
                n1 = n5;  // Restoring the original octal number
                // Loop to convert octal to decimal
                for (j = n1; j > 0; j = j / 10)
                {  
                    d = j % 10;
                    if (i == 1)
                        p = p * 1;
                    else
                        p = p * 8;

                    dec = dec + (d * p);
                    i++;
                }
                // Displaying the converted decimal number
                Console.Write("\nThe Octal Number : {0}\nThe equivalent Decimal  Number : {1} \n\n", n5, dec);
                break;
        }
    }
}

Sample Output:

Convert Octal number to Decimal number:                                                                     
------------------------------------------                                                                  
Input an octal number (using digit 0 - 7) :5                                                                
The Octal Number : 5                                                                                        
The equivalent Decimal  Number : 5

Flowchart:

C# Sharp Code Editor:

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