I can't seem to figure out how to do this problem. I'm getting stuck on the math with finding the checksum and how the code would look.
I know the code has a few things wrong with it and seems sloppy and could probably be written in a much smaller, more concise manner, but I am new to arrays and I am not very good at optimizing them yet.
import java.util.Arrays;
import java.util.Scanner;
public class ISBN{
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter ISBN:");
String isbnSTR = keyboard.nextLine();
String x;
int isbnARRAY[] = new int[10];
int total = 0;
for(int i = 0; i < isbnSTR.length(); i++){
x = ""+isbnSTR.charAt(i);
isbnARRAY[i] = Integer.parseInt(x);
total = isbnARRAY[i] * (10 - 1);
boolean isbnVALID = PassArray(isbnARRAY, i);
if (isbnVALID == true){
System.out.println("Your isbn number is valid.");
} else {
System.out.println("Your isbn number is NOT valid");
}
}
}
public static boolean PassArray(int isbnARRAY[], int total){
int result = 0;
int checkSum = 0;
int len = isbnARRAY.length;
for (int x = 0; x < len; x++){
result = (x * total);
checkSum = result % 11;
}
System.out.println(result);
boolean isbnVALID;
if (checkSum == 0){
isbnVALID=true;
} else {
isbnVALID=false;
}
return true;
}
}
I'm doing an assignment where the goal is to, among other things, to add two large integers. Here is my code, spread out into four files.
Main that we cannot change:
import java.util.*;
import MyUtils.MyUtil;
public class CSCD210HW7
{
public static void main(String [] args)throws Exception
{
int choice;
String num;
LargeInt one, two, three = null;
Scanner kb = new Scanner(System.in);
num = HW7Methods.readNum(kb);
one = new LargeInt(num);
num = HW7Methods.readNum(kb);
two = new LargeInt(num);
do
{
choice = MyUtil.menu(kb);
switch(choice)
{
case 1: System.out.println(one + "\n");
break;
case 2: System.out.println("The value of the LargeInt is: " + two.getValue() + "\n");
break;
case 3: num = HW7Methods.readNum(kb);
one.setValue(num);
break;
case 4: if(one.equals(two))
System.out.println("The LargeInts are equal");
else
System.out.println("The LargeInts are NOT equal");
break;
case 5: three = two.add(one);
System.out.printf("The results of %s added to %s is %s\n", one.getValue(), two.getValue(), three.getValue());
break;
case 6: HW7Methods.displayAscendingOrder(one, two, three);
break;
default: if(two.compareTo(one) < 0)
System.out.printf("LargeInt %s is less than LargeInt %s\n", two.getValue(), one.getValue());
else if(two.compareTo(one) > 0)
System.out.printf("LargeInt %s is greater than LargeInt %s\n", two.getValue(), one.getValue());
else
System.out.printf("LargeInt %s is equal to LargeInt %s\n", two.getValue(), one.getValue());
break;
}// end switch
}while(choice != 8);
}// end main
}// end class
LargeInt Class(Custom Class We Created)
public class LargeInt implements Comparable<LargeInt>
{
private int[]myArray;
private LargeInt()
{
this("0");
}
public LargeInt(final String str)
{
this.myArray = new int[str.length()];
for(int x = 0; x < this.myArray.length; x++)
{
this.myArray[x] = Integer.parseInt(str.charAt(x)+ "");
}
}
public LargeInt add(final LargeInt passedIn)
{
String stringOne = myArray.toString();
String stringTwo = passedIn.myArray.toString();
int r = Integer.parseInt(stringOne);
int e = Integer.parseInt(stringTwo);
int s = r + e;
return new LargeInt(""+s);
}
public void setValue(final String arrayString)
{
this.myArray = new int[arrayString.length()];
for(int x = 0; x < myArray.length; x++)
{
this.myArray[x]=arrayString.charAt(x);
}
}
#Override
public int compareTo(LargeInt passedIn)
{
if(passedIn == null)
{
throw new RuntimeException("NullExceptionError");
}
int ewu = 0;
int avs = 0;
if(this.myArray.length != passedIn.myArray.length)
{
return this.myArray.length - passedIn.myArray.length;
}
for(int i = 0; i < this.myArray.length -1; i++)
{
if(this.myArray[i] != passedIn.myArray[i])
{
return this.myArray[i]-passedIn.myArray[i];
}
}
return ewu-avs;
}
public int hashCode()
{
String p = "";
for(int f = 0; f < this.myArray.length; f++)
{
p += myArray[f];
}
return p.hashCode();
}
public String getValue()
{
String h = "";
for(int t = 0; t < this.myArray.length; t++)
{
h += myArray[t];
}
return h;
}
#Override
public boolean equals(Object jbo)
{
if(jbo == null)
{
return false;
}
if(!(jbo instanceof LargeInt))
{
return false;
}
LargeInt k =(LargeInt)jbo;
if(k.myArray.length != this.myArray.length)
{
return false;
}
for(int d = 0; d < this.myArray.length; d++)
{
if(k.myArray[d] != myArray[d])
{
return false;
}
}
return true;
}
#Override
public String toString()
{
String c = "";
for(int q = 0; q < this.myArray.length; q++)
{
c += myArray[q];
}
return "The LargeInt is: " + c;
}
}
HW7Methods File
import java.util.*;
import java.io.*;
public class HW7Methods
{
public static String readNum(Scanner kb)
{
String num = "";
System.out.print("Enter Your Large Int: ");
num = kb.nextLine();
return num;
}
public static void displayAscendingOrder(final LargeInt first, final LargeInt second, final LargeInt third)
{
String highestInt;
if(first.compareTo(second) >= 0 && first.compareTo(third) >= 0)
{
highestInt = first.getValue();
}
else if(second.compareTo(first) >= 0 && second.compareTo(third) >= 0)
{
highestInt = second.getValue();
}
else
{
highestInt = third.getValue();
}
String middleInt;
if(first.compareTo(second) >= 0 && first.compareTo(third) <= 0)
{
middleInt = first.getValue();
}
else if(second.compareTo(first) >= 0 && second.compareTo(third) <= 0)
{
middleInt = second.getValue();
}
else
{
middleInt = third.getValue();
}
String lowestInt;
if(first.compareTo(second) <= 0 && first.compareTo(third) <= 0)
{
lowestInt = first.getValue();
}
else if(second.compareTo(first) <= 0 && second.compareTo(third) <= 0)
{
lowestInt = second.getValue();
}
else
{
lowestInt = third.getValue();
}
System.out.println("The LargeInts in order are: " + lowestInt + ", " + middleInt + ", " + highestInt);
}
}
MyUtil file
package MyUtils;
import java.io.*;
import java.util.Scanner;
public class MyUtil
{
public static int menu(Scanner kb)
{
int userChoice;
System.out.println("1) Print First Int");
System.out.println("2) Print Second Int");
System.out.println("3) Add Different Int");
System.out.println("4) Check If Equal");
System.out.println("5) Add Large Ints");
System.out.println("6) Display In Ascending Order");
System.out.println("7) Compare Ints");
System.out.println("8) Quit");
kb = new Scanner(System.in);
System.out.print("Please Select Your Choice: ");
userChoice = kb.nextInt();
while(userChoice < 1 || userChoice > 8)
{
System.out.print("Invalid Menu Choice. Please Re-Enter: ");
userChoice = kb.nextInt();
}
return userChoice;
}
}
When I go to run this code, it prompts me for two Large Integers like it's supposed to. However, when I choose option 5 to add them, this is what I get:
Exception in thread "main" java.lang.NumberFormatException: For input string: "[I#55f96302"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
at LargeInt.add(LargeInt.java:24)
at CSCD210HW7.main(CSCD210HW7.java:41)
I've never seen that type of error before. Can someone tell me what is going on?
For input string: "[I#55f96302
That is not a "proper" String you are trying to parse here.
This is what an int[] looks like when you call toString() on it.
String stringOne = myArray.toString();
Why do you do that? What is that supposed to do?
int r = Integer.parseInt(stringOne);
int e = Integer.parseInt(stringTwo);
int s = r + e;
From the looks of it, you try to handle "large" ints with your LargeInt class by somehow storing them in an array of ints. That's okay, BigInteger also works like that (more or less), but you cannot just do calculations by trying to convert back to int (after all those numbers are too big for int arithmetic to handle, even if you do the string parsing properly).
this is my program:
public class ArmstrongNumber {
public static void main(String args[]) {
int n = 0, temp = 0, r = 0, s = 0;
Scanner in = new Scanner(System.in);
System.out.println("Enter a number ");
if (in.hasNextInt()) {
n = in.nextInt(); // if there is another number
} else {
n = 0;
}
temp = n;
while (n != 0) {
r = n % 10;
s = s + (r * r * r);
n = n / 10;
}
if (temp == s) {
System.out.println(n + " is an Armstrong Number");
} else {
System.out.println(n + " is not an Armstrong Number");
}
}
}
output:
Exception in thread "main" java.lang.NoClassDefFoundError
I tried it using DataInputStream but still getting same error.
// To check the given no is Armstrong number (Java Code)
class CheckArmStrong{
public static void main(String str[]){
int n=153,a, b=0, c=n;
while(n>0){
a=n%10; n=n/10; b=b+(a*a*a);
System.out.println(a+" "+n+" "+b); // to see the logic
}
if(c==b) System.out.println("Armstrong number");
else System.out.println(" Not Armstrong number");
}
}
Find any digit is Armstrong number or not using loop
for(int arm_num = 0 ; arm_num < 100000 ; arm_num++)
{
String[] data = String.valueOf(arm_num).split("(?<=.)");
int lngth = String.valueOf(arm_num).length();
int arm_t_num = 0;
int ary[] = new int[lngth];
for(int i = 0 ; i < lngth ; i++)
{
ary[i] = Integer.parseInt(data[i]);
for(int x = 0 ; x < lngth-1 ; x++)
{
ary[i] = ary[i] * Integer.parseInt(data[i]);
}
arm_t_num+=ary[i];
}
if(arm_num == arm_t_num)
{
System.out.println("Number is ArmStrong : "+arm_num);
}
}
you need to set CLASS_PATH variable and point it to where ever your class file is
then this should work
I have tried it locally, refer my answer to check how to set class path and how to compile and run java code using command prompt
//This is my program to check whether the number is armstrong or not!!
package myprogram2;
public class Myprogram2 {
public static void main(String[] args)
{
String No="407";
int length_no=No.length();
char[] S=new char[length_no];
int[] b = new int[length_no];
int arm=0;
for(int i=0;i<length_no;i++)
{
S[i]=No.charAt(i);
b[i]=Character.getNumericValue(S[i]);
//System.out.print(b[i]);
arm=arm + (b[i]*b[i]*b[i]);
System.out.println(arm);
}
//System.out.println(" is the number \n now Checking for its Armstrong condition");
int orgno = Integer.parseInt(No);
if (orgno==arm)
System.out.println("YESm its an armstrong");
else
System.out.println("\n<<Not an armstrong>>");
//System.out.println(length_no);
System.out.println("Original number is "+orgno);
System.out.println("Sum of cubes "+arm);
}
}
There are a couple of nice String-based solutions and numeric solutions with single-letter variable names.
Consider this to make sense of how it works numerically, which includes a couple of interesting numeric tricks:
import java.io.*;
public class Armstrong
{
public static void main(String args[]) throws IOException
{
InputStreamReader read = new InputStreamReader(System.in);
BufferedReader in = new BufferedReader(read);
int modifiedNumber, originalNumber, modifiedNumberWithUnitsDigitZero,
unitsDigit, runningSum;
System.out.println("Enter your number:");
modifiedNumber = Integer.parseInt(in.readLine());
runningSum = 0;
originalNumber = modifiedNumber;
while(modifiedNumber > 0)
{
modifiedNumberWithUnitsDigitZero = modifiedNumber / 10 * 10;
unitsDigit = modifiedNumber - modifiedNumberWithUnitsDigitZero;
runningSum += unitsDigit * unitsDigit * unitsDigit;
modifiedNumber = modifiedNumber / 10;
}
System.out.println("The number " + originalNumber
+ (originalNumber == runningSum ? " IS" : " is NOT")
+ " an Armstrong number because sum of cubes of digits is " + runningSum);
}
}
import java.util.Scanner;
public class Amst {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
System.out.println("Enter The No. To Find ArmStrong Check");
int i = sc.nextInt();
int sum = 0;
for(int j = i; j>0 ; j = j/10){
sum = sum + ((j%10)*(j%10)*(j%10));
}
if(sum == i)
System.out.println("Armstrong");
else
System.out.println("Not Armstrong");
}
}
For 'N' digit amstrong number
package jjtest;
public class Amstrong {
public static void main(String[] args) {
// TODO Auto-generated method stub
int num=54748;
int c=0;
int temp=num;
int b=1;
int length = (int)(Math.log10(num)+1);
while(num>0){
int r = num%10;
num=num/10;
int a =1;
for(int i=1;i<=length;++i){
b=b*r;
}
c = c + b;
b=1;
}
System.out.println(c);
if(c==temp){
System.out.println("its an amstrong number");
}else{
System.out.println("its not an amstrong number");
}
}
}
This is the simple logic for Armstrong number program :
for (int i = number; i > 0; i = i / 10)
{
remainder = i % 10;
sum = sum + remainder * remainder * remainder;
}
if(sum == number)
{
System.out.println("\n" + number + " is an Armstrong Number\n");
}
Reference :
http://topjavatutorial.com/java/java-programs/java-program-to-check-if-a-number-is-armstrong-number/
import java.util.Scanner;
/* a number is armstrong if the sum of cubes if individual digits of
a number is equal to the number itself.for example, 371 is
an armstrong number. 3^3+7^3+1^3=371.
some others are 153,370,407 etc.*/
public class ArmstrongNumber {
public static void main(String args[]) {
int input, store, output=0, modolus;
Scanner in = new Scanner(System.in);
System.out.println("Please enter a number for ckecking.");
input = in.nextInt();
store = input;
while(input != 0) {
modolus = input % 10;
output = output + (modolus * modolus * modolus);
input = input / 10;
}
System.out.println(output);
if(store == output) {
System.out.println("This is an armstrong number.");
} else {
System.out.println("This is not an armstrong number.");
}
in.close();
}
}
import java.util.*;
public class ArmstrongNumber
{
public static void main( String[] args )
{
int n = 0, temp = 0, r = 0, s = 0;
Scanner in = new Scanner(System.in);
System.out.println("Enter a number ");
if (in.hasNextInt()) {
n = in.nextInt(); // if there is another number
} else {
n = 0;
}
temp = n;
while (n != 0) {
r = n % 10;
s = s + (r * r * r);
n = n / 10;
}
if (temp == s) {
System.out.println(temp + " is an Armstrong Number");
} else {
System.out.println(temp + " is not an Armstrong Number");
}
}
}
You missed to import java.util package
Change n to temp in S.O.P
import java.util.Scanner;
public class AmstrongNumber {
public static void main(String[] args) {
System.out.println("Enter the number");
Scanner scan=new Scanner(System.in);
int x=scan.nextInt();
int temp2=0;
String s1 = Integer.toString(x);
int[] a = new int[s1.length()];
int[] a1 = new int[s1.length()];
for (int i = 0; i < s1.length(); i++){
a[i] = s1.charAt(i)- '0';
int temp1=a[i];
a1[i]=temp1*temp1*temp1;
}
for (int i = 0; i < s1.length(); i++){
temp2=temp2+a1[i];
if(i==s1.length()-1){
if(x==temp2){
System.out.println("Amstrong num");
}else{
System.out.println("Not !");
}
}
}
}
}
private static boolean isArmstrong(int num) {
int totalSum = 0;
int copyNum = num;
while (num != 0) {
int reminder = num % 10;
int cubeOfReminder = reminder * reminder * reminder;
totalSum = totalSum + cubeOfReminder;
num = num / 10;
}
if (copyNum == totalSum)
return true;
return false;
}
public class Testamstrong
{
public static void main(String...strings) {
int num = 153,temp;
temp = num;
if(temp == amstrongNumber(num)) {
System.out.println("Number is amstrong number...");
}
else {
System.out.println("Number is not amstrong number...");
}
}
public static int amstrongNumber(int num) {
int count=0,sum=0;
count = String.valueOf(num).length();
char[] ch = String.valueOf(num).toCharArray();
for(char ch1:ch) {
int num1 = Character.getNumericValue(ch1);
sum += Math.pow(num1, count);
}
return sum;
}
}
Find Armstrong number using for loops (with example)
import java.util.*;
public class ArmstorngNumber {
public static void main(String args[]) {
int cube, num, quo, n;
int s = 0;
do
{
System.out.println("Enter Your Number");
Scanner sc = new Scanner(System.in);
num = sc.nextInt();//153
n = num;
for (int i = 0; i < 10; i++) {
int rem = num % 10;//3
quo = num / 10; //15
cube = rem * rem * rem;//9
s = s + cube;//0+9
num = quo;//0
}
System.out.println(s);
System.out.println(n);
if (s == n) {
System.out.println("The number is Armstrong");
System.out.println("-------------------------------------");
}
else {
System.out.println("The number is not Armstrong");
System.out.println("-------------------------------------");
}
}
while (n > 0);
}
}
Check the Armstrong number of any number [java] [Armstrong]
import java.util.*;
public class Armstrong {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("enter any number?");
int x = sc.nextInt();
int n=0;
int number = x;
int j =x;
int result = 0 ,remainder;
while (x!=0) {
x/=10;
++n;
}
for(;j>0 ;j=j/10) {
remainder=j%10;
result+=Math.pow(remainder, n);
}
if (number==result) {
System.out.print(number +" is Armstrong ");
}
else
System.out.print(number +" is not Armstrong");
}
}
here is my code, please check if this works for you!
import java.util.Scanner;
public class Armstromg {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Please enter the number: ");
int num = sc.nextInt();
int length = 0;
int temp1 = num;
while(temp1 != 0) {
temp1/=10;
length+=1;
}
int result = 1;
int temp2 = num;
for(int i = 1; i <= length; i++) {
temp2 = temp2 % 10;
result*=Math.pow(temp2,length);
}
if(result == num) {
System.out.print("The number is an armstrong number!");
} else {
System.out.print("The number is not an armstrong number");
}
}
}
package Loops;
public class ArmStrongNumber {
public static void main(String[] args) {
int digit1, digit2, digit3;
int number = 153;
int temp = number;
digit1 = number % 10;
number = number / 10;
digit2 = number % 10;
number = number / 10;
digit3 = number % 10;
if ((digit1 * digit1 * digit1) + (digit2 * digit2 * digit2) + (digit3 * digit3 * digit3) == temp) {
System.out.println(+temp + " Number is Armstrong ");
} else {
System.out.println("Number is not Armstrong");
}
}
}
//Not limited to 3 digit integers
public static void main(String[] args)
{
int num = 54748,a,sum=0;
int x = num;
int p =Integer.toString(num).length();
while (num !=0)
{
a = num%10;
num = num/10;
sum = sum + (int) Math.pow(a, p);
}
if (x==sum)
System.out.println("Its an Armstrong number");
else
System.out.println("Not an Armstrong number");
}
}
Scanner input = new Scanner (System.in);
int num , counter = 0 ,temp;
System.out.print("Enter Nmber :");
num = input.nextInt();
int lnum = num;
while ( num != 0 ){
num = num/10 ;
counter++;
}
int store_num_keyboard_input = lnum;
int new_tot = 0;
int c = counter;
while(lnum > 0){
temp = lnum % 10;
lnum = lnum / 10 ;
int m = 0; //m is counter
int tot = 1;
while (m != c){
tot = tot * temp;
m++;
}
new_tot = new_tot + tot;
}
System.out.println("new total "+ new_tot );
if(new_tot == store_num_keyboard_input){
System.out.println(store_num_keyboard_input + " is an Armstrong number" );
}
else{
System.out.println(store_num_keyboard_input + " is not an Armstrong number" );
}
My answer using JAVA 8
tested for..[1, 153, 370, 371, 407]
public class Armstrong {
public static boolean isArmstrong(int num) {
return num == getArmstrongSum(num);
}
public static int getArmstrongSum(int num) {
int pow = String.valueOf(num).length();
return IntStream.iterate(num, i -> i / 10)
.limit(pow)
.map(i -> (int) Math.pow(i % 10, 3))
.sum();
}
public static void main(String[] args) {
System.out.println(isArmstrong(153));
}
}
Thank you.
I am creating a code that allows you to convert a binary number to a decimal number and vice versa. I have created a code that converts decimal to binary but can not workout how to implement the binary to decimal aspect.
My code for decimal to binary is below:
import java.util.*;
public class decimalToBinaryTest
{
public static void main (String [] args)
{
int n;
Scanner in = new Scanner(System.in);
System.out.println("Enter a positive interger");
n=in.nextInt();
if(n < 0)
{
System.out.println("Not a positive interger");
}
else
{
System.out.print("Convert to binary is: ");
binaryform(n);
}
}
private static Object binaryform(int number)
{
int remainder;
if(number <= 1)
{
System.out.print(number);
return " ";
}
remainder= number % 2;
binaryform(number >> 1);
System.out.print(remainder);
{
return " ";
}
}
}
An explanation to how the binary to decimal code work would help as well.
I have tried the method of the least significant digit*1 then the next least *1*2 then *1*2*2 but can not get it to work.
Thank you #korhner I used your number system with arrays and if statements.
This is my working code:
import java.util.*;
public class binaryToDecimalConvertor
{
public static void main (String [] args)
{
int [] positionNumsArr= {1,2,4,8,16,32,64,128};
int[] numberSplit = new int [8];
Scanner scanNum = new Scanner(System.in);
int count1=0;
int decimalValue=0;
System.out.println("Please enter a positive binary number.(Only 1s and 0s)");
int number = scanNum.nextInt();
while (number > 0)
{
numberSplit[count1]=( number % 10);
if(numberSplit[count1]!=1 && numberSplit[count1] !=0)
{
System.out.println("Was not made of only \"1\" or \"0\" The program will now restart");
main(null);
}
count1++;
number = number / 10;
}
for(int count2 = 0;count2<8;count2++)
{
if(numberSplit[count2]==1)
{
decimalValue=decimalValue+positionNumsArr[count2];
}
}
System.out.print(decimalValue);
}
}
sample:
00000100
0 - 1
0 - 2
1 - 4
0 - 8
0 - 16
0 - 32
0 - 64
0 - 128
Sum values with bit 1 = 4
Good luck!
int decimal = Integer.parseInt("101101101010111", 2);
or if you prefer to doit your self
double output=0;
for(int i=0;i<str.length();i++){
if(str.charAt(i)== '1')
output=output + Math.pow(2,str.length()-1-i);
}
Here is a program which does that.
Make sure the integers you give to int and not too large.
import java.util.Scanner;
public class DecimalBinaryProgram {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
while (true){
System.out.println("Enter integer in decimal form (or # to quit):");
String s1 = in.nextLine();
if ("#".equalsIgnoreCase(s1.trim())){
break;
}
System.out.println(decimalToBinary(s1));
System.out.println("Enter integer in binary form (or # to quit):");
String s2 = in.nextLine();
if ("#".equalsIgnoreCase(s2.trim())){
break;
}
System.out.println(binaryToDecimal(s2));
}
}
private static String decimalToBinary(String s){
int n = Integer.parseInt(s, 10);
StringBuilder sb = new StringBuilder();
if (n==0) return "0";
int d = 0;
while (n > 0){
d = n % 2;
n /= 2;
sb.append(d);
}
sb = sb.reverse();
return sb.toString();
}
private static String binaryToDecimal(String s){
int degree = 1;
int n = 0;
for (int k=s.length()-1; k>=0; k--){
n += degree * (s.charAt(k) - '0');
degree *= 2;
}
return n + "";
}
}
Of course for this method binaryToDecimal you can just do:
private static String binaryToDecimal(String s){
int n = Integer.parseInt(s, 2);
return n + "";
}
but I wanted to illustrate how you can do that explicitly.
do you want this?
private double dec(String s, int i) {
if (s.length() == 1) return s.equals("1") ? Math.pow(2, i) : 0;
else return (s.equals("1") ? Math.pow(2, i) : 0) + dec(s.substring(0, s.length() - 1), i - 1);
}
dec("101011101",0);
This is a version of a binary to decimal converter. I have used plenty of comments also. Just taught I would like to share it. Hope it is of some use to somebody.
import java.util.Scanner;
public class BinaryToDecimal
{
public static void main(String args[])
{
Scanner input = new Scanner(System.in);
System.out.println("Enter a binary number: ");
String binary = input.nextLine(); // store input from user
int[] powers = new int[16]; // contains powers of 2
int powersIndex = 0; // keep track of the index
int decimal = 0; // will contain decimals
boolean isCorrect = true; // flag if incorrect input
// populate the powers array with powers of 2
for(int i = 0; i < powers.length; i++)
powers[i] = (int) Math.pow(2, i);
for(int i = binary.length() - 1; i >= 0; i--)
{
// if 1 add to decimal to calculate
if(binary.charAt(i) == '1')
decimal = decimal + powers[powersIndex]; // calc the decimal
else if(binary.charAt(i) != '0' & binary.charAt(i) != '1')
{
isCorrect = false; // flag the wrong input
break; // break from loop due to wrong input
} // else if
// keeps track of which power we are on
powersIndex++; // counts from zero up to combat the loop counting down to zero
} // for
if(isCorrect) // print decimal output
System.out.println(binary + " converted to base 10 is: " + decimal);
else // print incorrect input message
System.out.println("Wrong input! It is binary... 0 and 1's like.....!");
} // main
} // BinaryToDecimal
I've written a converter that accepts both strings and ints.
public class Main {
public static void main(String[] args) {
int binInt = 10110111;
String binString = "10110111";
BinaryConverter convertedInt = new BinaryConverter(binInt);
BinaryConverter convertedString = new BinaryConverter(binString);
System.out.println("Binary as an int, to decimal: " + convertedInt.getDecimal());
System.out.println("Binary as a string, to decimal: " + convertedString.getDecimal());
}
}
public class BinaryConverter {
private final int base = 2;
private int binaryInt;
private String binaryString;
private int convertedBinaryInt;
public BinaryConverter(int b) {
binaryInt = b;
convertedBinaryInt = Integer.parseInt(Integer.toString(binaryInt), base);
}
public BinaryConverter(String s) {
binaryString = s;
convertedBinaryInt = Integer.parseInt(binaryString, base);
}
public int getDecimal() {
return convertedBinaryInt;
}
}
public static void main(String[] args)
{
System.out.print("Enter a binary number: ");
Scanner input = new Scanner(System.in);
long num = input.nextLong();
long reverseNum = 0;
int decimal = 0;
int i = 0;
while (num != 0)
{
reverseNum = reverseNum * 10;
reverseNum = num % 10;
decimal = (int) (reverseNum * Math.pow(2, i)) + decimal;
num = num / 10;
i++;
}
System.out.println(decimal);
}
Currently, I'm trying to read in a .dat file and assign various lines into an array. The file will provide items like "a100" and "q80" which I will have to separate into categories by letter and then have different grades as an array for each category. Right now, this is what I have, but I'm getting a lot of run-time errors when I try various things. Is there something I'm missing here?
Some of the errors I'm having:
When I execute case 'P', it prints this out: WeightedGrades#13105f32
When I try to execute cases C, A or D, this happens: Exception in thread "main" java.lang.NoSuchMethodError: WeightedGrades.deleteGrade(Ljava/lang/String;)Z
WeightedGrades class:
public class WeightedGrades {
private String name;
private int numGrades;
private String[] grades;
public static final double ACTV_WT = 0.05, QUIZ_WT = 0.10, PROJ_WT = 0.25, EXAM_WT = 0.30, FINAL_EXAM_WT = 0.30;
public WeightedGrades(String nameIn, int numGradesIn, String[] gradesIn) {
name = nameIn;
numGrades = numGradesIn;
grades = gradesIn;
}
public String getName() {
return name;
}
public int getNumGrades() {
return numGrades;
}
public String[] getGrades() {
return grades;
}
public double[] gradesByCategory(char categoryChar) {
int count = 0;
for (int i = 0; i < grades.length; i++) {
if (categoryChar == grades[i].charAt(0)) {
count++;
}
}
double[] gradesNew = new double[count];
count = 0;
for( int i = 0; i < numGrades; i++) {
if (categoryChar == grades[i].charAt(0)) {
gradesNew[count] = Double.parseDouble(grades[i].substring(1));
count++;
}
}
return gradesNew;
}
public String toString() {
String result = "\tStudent Name: " + getName()
+ "\n\tActivities: " + gradesByCategory('A')
+ "\n\tQuizzes: " + gradesByCategory('Q')
+ "\n\tProjects: " + gradesByCategory('P')
+ "\n\tExams: " + gradesByCategory('E')
+ "\n\tFinal Exam: " + gradesByCategory('F')
+ "\n\tCourse Average: " + courseAvg();
return result;
}
public void addGrade(String newGrade) {
if (numGrades >= grades.length) {
increaseGradesCapacity();
}
grades[numGrades] = newGrade;
numGrades++;
}
public boolean deleteGrade(String gradeDelete) {
boolean delete = false;
int deleteIndex = -1;
for (int i = 0; i < numGrades; i++) {
if (gradeDelete.charAt(0) == grades[i].charAt(0) &&
Double.parseDouble(gradeDelete.substring(1))
== Double.parseDouble(grades[i].substring(1))) {
deleteIndex = i;
}
}
if (deleteIndex > -1) {
for (int i = deleteIndex; i < numGrades - 1; i++) {
grades[i] = grades[i + 1];
}
grades[numGrades - 1] = "";
numGrades--;
return true;
}
else {
return false;
}
}
public void increaseGradesCapacity() {
String[] temporary = new String[grades.length + 1];
for (int i = 0; i < grades.length; i++) {
temporary[i] = grades[i];
}
grades = temporary;
}
public double average(double[] newArray) {
if (newArray.length == 0) {
return 0.0;
}
double sum = 0;
double average = 0;
for ( int i = 0; i < newArray.length; i++) {
sum += newArray[i];
average = sum / newArray.length;
}
return average;
}
public double courseAvg() {
double actvAvg = 0.0;
double quizAvg = 0.0;
double projAvg = 0.0;
double examAvg = 0.0;
double finalAvg = 0.0;
double avg = 0.0;
if (!numGrades.length == 0) {
avg = actvAvg * ACTV_WT + quizAvg * QUIZ_WT + projAvg * PROJ_WT + examAvg * EXAM_WT + finalAvg * FINAL_EXAM_WT;
}
return avg;
}
}
Second class
import java.util.Scanner;
import java.io.IOException;
public class WeightedGradesApp {
public static void main(String[] args) throws IOException {
String name = "";
int numGrades = 0;
String[] grades = new String[13];
String code = "";
String gradeAdd = "";
String gradeDelete = "";
String categoryIn = "";
WeightedGrades student = new WeightedGrades(name, numGrades, grades);
Scanner userInput = new Scanner(System.in);
if (args == null) {
System.out.println("File name was expected as a run argument.");
System.out.println("Program ending.");
return;
}
else {
System.out.println("File read in and WeightedGrades object created.");
System.out.println("");
System.out.println("Player App Menu");
System.out.println("P - Print Report");
System.out.println("C - Print Category");
System.out.println("A - Add Grade");
System.out.println("D - Delete Grade");
System.out.println("Q - Quit ");
do {
System.out.print("Enter Code [P, C, A, D, or Q]: ");
code = userInput.nextLine();
if (code.length() == 0) {
continue;
}
code = code.toUpperCase();
char codeChar = code.charAt(0);
switch (codeChar) {
case 'P':
System.out.println(student.toString());
break;
case 'C':
System.out.print(" Category: ");
categoryIn = userInput.nextLine();
char categoryChar = categoryIn.charAt(0);
System.out.println(student.gradesByCategory(categoryChar));
break;
case 'A':
System.out.print(" Grade to add: ");
gradeAdd = userInput.nextLine();
student.addGrade(gradeAdd);
break;
case 'D':
System.out.print(" Grade to delete: ");
gradeDelete = userInput.nextLine();
boolean isDeleted = student.deleteGrade(gradeDelete);
if (isDeleted) {
System.out.println(" Grade deleted");
}
else {
System.out.println(" Grade not found");
}
break;
case 'Q':
break;
default:
}
} while (!code.equalsIgnoreCase("Q"));
}
}
}
For starters your code as is doesn't compile due to the line
if (!numGrades.length == 0) {
This is because numGrades is an int it is a primative type and therefore does not have any property length. I'm assuming what you want here is
if (numGrades != 0) {
Also as I mentioned you are not dealing with reading in the file, you supply the file name but never actually read it, I suggest you look at the Java tutorial on File IO
On this note you do the check args == null this will not check that no args are supplied, try it. what you want is args.length == 0
On your other error I have no idea how you even produced that... I'm assuming it is using an older compiled version of the class where the methods have not being written.