Java Programming Assignment 1

Problem C

Write another Java application program to find and display all of the Perfect Numbers between 2 and 500 (inclusive). A Perfect Number is a number for which the sum of its divisors (between 1 and number/2, inclusive) is equal to the number. For example, 6 is a Perfect number (1 + 2 + 3 = 6).

You MUST include in this program:

1. for loops

2. % (modulus) operator to determine if a number is a divisor

3. static final (class-scope) variables for 2 and 500.

4. OPTIONAL: static method to return a boolean value (true IF THE PARAMETER IS A PERFECT NUMBER) by finding and adding the divisors (between 1 and parameter/2, inclusive) of the integer parameter and comparing the sum to the parameter.

DO NOT USE CLASS-SCOPE VARIABLES unless they're final AND static.

Do not use any input for these programs!

Solution

/*

Name of program: Display Information given in Problem A

Programmer's name: ABC

Current Date: DD/MM/YYYY

Computer system and compiler you are using: Win 8, JDK 1.7

Brief description of the program (1-5 sentences): LINE UP YOUR INFORMATION, INCLUDING PUTTING NEWLINES AS SHOWN. You don't need any variables.

Variable names (if any) and descriptions of what they represent: Used /n (newline), %5s (for 5 empty space at the beginning of line)

*/

public class HW1_A 

{

/** @param args */

public static void main(String[] args) 

{

// HW1 Problem A

System.out.println("CIS 35A Student Learning Outcomes\n");

System.out.printf("Outcome 1:\n%5sRead, analyze and explain intermediate level Java\n%5sprograms.\n\n", " ", " ");

System.out.printf("Outcome 2:\n%5sDesign solutions for intermediate level problems using\n%5sappropriate design methodology incorporating object-\n%5soriented intermediate programming constructs.\n\n", " ", " ", " ");

System.out.printf("Outcome 3:\n%5sCreate algorithms, code, document, debug, and test\n%5sintermediate level Java programs.", " ", " ");

}

}

/*

Program Output:

Student Learning Outcomes

Outcome 1:

     Read, analyze and explain intermediate level Java

     programs.

Outcome 2:

     Design solutions for intermediate level problems using

     appropriate design methodology incorporating object-

     oriented intermediate programming constructs.

Outcome 3:

     Create algorithms, code, document, debug, and test

     intermediate level Java programs.

*/

/*

Name of program: Problem B - Rotate the int to the right by 4 bits in loop 3 times

Programmer's name: ABC

Current Date: DD/MM/YYYY

Computer system and compiler you are using: Win 8, JDK 1.7

Brief description of the program (1-5 sentences): Write another Java application program which initializes an int variable to 0x468A does the following in a loop 3 times:

- rotate the int to the right by 4 bits and store back in the int var. (be sure to save the "right-most" 4 bits in a temporary variable before shifting, and DON'T sign-extend) 

- print the var. in hexadecimal (use %X with System.out.printf)

Variable names (if any) and descriptions of what they represent: i_origNum - to Store original number, i_tempNum - to save the "right-most" 4 bits in a temporary variable, i_resultNum - to store result value

*/

public class HW1_B 

{

/** @param args */

public static void main(String[] args) 

{

int i_origNum = 0x468A;

int i_resultNum = i_origNum; // Set default value

// loop 3 times

for (int i = 0; i < 3 ; i++)

{

int i_tempNum = 0;

i_tempNum = (i_resultNum & 0x00F) << 12; // use masking to get last 4 binary digit and left shift by 12 bits put them to right most position

i_resultNum = (i_resultNum >>> 4) + i_tempNum; // rotate right by 4 bits and than add temp number as right most digit

System.out.printf("%X %X %X\n", i_origNum, i_tempNum, i_resultNum); // print all 3 numbers in hex format

}

}

}

/*

Program Output:

468A A000 A468

468A 8000 8A46

468A 6000 68A4

*/

/*

Name of program: Problem C - Perfect Number

Programmer's name: ABC

Current Date: DD/MM/YYYY

Computer system and compiler you are using: Win 8, JDK 1.7

Brief description of the program (1-5 sentences): Write another Java application program to find and display all of the Perfect Numbers between 2 and 500 (inclusive). A Perfect Number is a number for which the sum of its divisors (between 1 and number/2, inclusive) is equal to the number. For example, 6 is a Perfect number (1 + 2 + 3 = 6). You MUST include in this program:

1. for loops

2. % (modulus) operator to determine if a number is a divisor

3. static final (class-scope) variables for 2 and 500.

4. OPTIONAL: static method to return a boolean value (true IF THE PARAMETER IS A PERFECT NUMBER) by finding and adding the divisors (between 1 and parameter/2, inclusive) of the integer parameter and comparing the sum to the parameter.

Variable names (if any) and descriptions of what they represent: 

*/

public class HW1_C 

{

public static final int i_rangeMin = 2; // Search between 2 to 500 (inclusive)

public static final int i_rangeMax = 500;

public static void main(String[] args) 

{

for (int i=i_rangeMin; i <= i_rangeMax; i++) // Outer loop go through all number between 2-500

{

int i_sumOfDivisors = 0;

for (int j=1; j <= (i/2); j++) // Inner loop search for divisors and 

{

if(i%j == 0)

i_sumOfDivisors = i_sumOfDivisors + j; // Sum of divisors

}

if (i_sumOfDivisors == i) // Comparison to check whether it is a Perfect number

System.out.println(i);

}

}

}

/*

Program Output:

6 

28 

496 

 */