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Question

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An Odious number is a positive whole number. Which has odd number of 1’s in its Binary\nequivalent.

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A few Odious numbers are : 2, 4, 7, 8, 11, 13, etc.

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Design a program to accept a positive whole number. Find the binary equivalent of the\nnumber and count the number of 1’s in it and display whether it is an Odious number or not\nwith an appropriate message. The proper error message should be displayed for the\nnegative input.

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Test your program with the sample data and some random data:

\n\n
\nINPUT: 11\nOUTPUT:\nBINARY EQUIVALENT = 1011\nNUMBER OF 1’S = 3\n11 IS AN ODIOUS NUMBER
\n\n
INPUT: 15\nOUTPUT:\nBINARY EQUIVALENT = 1111\nNUMBER OF 1’S = 4\n15 IS NOT AN ODIOUS NUMBER
\n\n
INPUT: -17\nOUTPUT: INVALID INPUT
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Solution

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Algorithms

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For main():

\n
    \n
  1. Prompt the user to enter a positive whole number.
    2. \n
  2. Read the user's input and store it in a variable num.
    3. \n
  3. If num is negative, display an error message and terminate the program.
    4. \n
  4. Convert num to its binary equivalent using the toBinaryString method.
    5. \n
  5. Count the number of ones in the binary string using the countOnes method.
    6. \n
  6. If the number of ones is odd, print that num is an Odious number.
    7. \n
  7. If the number of ones is even, print that num is not an Odious number.
    8. \n
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For toBinaryString():

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    \n
  1. Initialize a variable binaryString to the empty string.
    2. \n
  2. While num is greater than 0:\n
      \n
    1. Prepend the remainder of num divided by 2 to binaryString.
      2. \n
    2. Divide num by 2.
      3. \n
    \n
    3. \n
  3. Return binaryString.
    4. \n
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For countOnes():

\n
    \n
  1. Initialize a variable count to 0.
    2. \n
  2. Iterate through each character c in the string str:\n
      \n
    1. If c is '1', increment count by 1.
      2. \n
    \n
    3. \n
  3. Return count.
    4. \n
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Source Code

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import java.util.Scanner;\n\npublic class Main {\n    public static void main(String[] args) {\n        // Create a Scanner object to read input from the user\n        Scanner scan = new Scanner(System.in);\n\n        // Prompt the user to enter a positive whole number\n        System.out.print(\"Enter a positive whole number: \");\n        int num = scan.nextInt();\n\n        // Close the scanner to free up resources\n        scan.close();\n\n        // If the number is negative, display an error message and terminate the program\n        if (num < 0) {\n            System.out.println(\"Error: number must be positive.\");\n            return;\n        }\n\n        // Convert the number to its binary equivalent\n        String binaryString = toBinaryString(num);\n\n        // Count the number of ones in the binary string\n        int numOnes = countOnes(binaryString);\n\n        // Print the binary equivalent of the number\n        System.out.println(\"Binary equivalent: \" + binaryString);\n\n        //Print the number of ones in the binary string\n        System.out.println(\"Number of 1's: \" + numOnes);\n\n        // If the number of ones is odd, print that the number is an Odious number\n        if (numOnes % 2 == 1) {\n            System.out.println(num + \" is an Odious number.\");\n        }\n        // Otherwise, print that the number is not an Odious number\n        else {\n            System.out.println(num + \" is not an Odious number.\");\n        }\n    }\n\n    /**\n     * Converts the given number to its binary equivalent as a string.\n     * @param num the number to convert\n     * @return the binary equivalent of the number as a string\n     */\n    private static String toBinaryString(int num) {\n        String binaryString = \"\";\n        // Iteratively divide the number by 2 and prepend the remainder to the binary string\n        // until the number becomes 0\n        while (num > 0) {\n            binaryString = (num % 2) + binaryString;\n            num /= 2;\n        }\n        return binaryString;\n    }\n\n    /**\n     * Counts the number of ones in the given string.\n     * @param str the string to count ones in\n     * @return the number of ones in the string\n     */\n    private static int countOnes(String str) {\n        int count = 0;\n        // Iterate through each character in the string and count the ones\n        for (int i = 0; i < str.length(); i++) {\n            if (str.charAt(i) == '1') {\n                count++;\n            }\n        }\n        return count;\n    }\n}
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Variable tables

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Method - main()

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
VariableTypeDescription
scanScannerA Scanner object used to read input from the user
numintThe positive whole number entered by the user
binaryStringStringThe binary equivalent of num as a string
numOnesintThe number of ones in binaryString
argsString[]The command-line arguments passed to the program (unused in this program)
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Method - toBinaryString()

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
VariableTypeDescription
numintThe number to convert to a binary string
binaryStringStringThe binary equivalent of num as a string (initialized to the empty string)
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Method - countOnes()

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
VariableTypeDescription
strStringThe string to count the number of ones in
countintThe number of ones in str (initialized to 0)
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