I want the user to input a DNA sequence, if it doesn't have the letters A, C, T, or G then it should print out an error. But how can I scan the string entered for those specific characters in the constructot method DNASequence?
heres what I have so far.
import java.util.*;
public class DNASequence {
private String DNASequence;//create a private static variable that can be accessed
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.println("Please input a sequence of DNA: ");
String DNAInput = input.nextLine();
}
public DNASequence(String DNAStrand){//Constructor Method that takes parameter a string and checks to see if its only A, T, C, G.
DNASequence = DNAStrand;
// Invoke the countLetters method to count each letter
int[] counts = countLetters(DNAStrand.toUpperCase());
// Display results
for (int i = 0; i < counts.length; i++) {
if (counts[i] != 0)
System.out.println((char)('a' + i) + " appears " +
counts[i] + ((counts[i] == 1) ? " time" : " times"));
}
}
/** Count each letter in the string */
public static int[] countLetters(String s) {
int[] counts = new int[26];
for (int i = 0; i < s.length(); i++) {
if (Character.isLetter(s.charAt(i)))
counts[s.charAt(i) - 'a']++;
}
return counts;
}
public String toString(){//Method that just returns the stored sequence
return DNASequence;
}
private static char NucleotideBaseCount(char BaseCount){//Method to count bases
}
private static boolean isSubsequenceOf(String DNAStrand){
}
}
You could use the following regular expression for this: ^[ACTG]+$.
To match the input string against the regex, use String.matches().
Here in a sample implementation based on #NPE 's comment:
import java.util.*;
public class DNASequence
{
private String DNASequence = null; //create a private static variable that can be accessed
public static void main(String[] args)
{
System.out.println("Please input a sequence of DNA: ");
DNASequence dnaS = new DNASequence((new Scanner(System.in)).nextLine().toUpperCase());
}
//Constructor Method that takes parameter a string and checks to see if its only A, T, C, G.
public DNASequence(String DNAStrand) throws IllegalArgumentException
{
if (DNAStrand.matches("^[ATCG]+$"))
{
DNASequence = DNAStrand;
}
else
{
throw new IllegalArgumentException("DNA Sequences should only contain A, T, C, G charaters");
}
}
/** Count each letter in the string */
public int[] countLetters() throws IllegalArgumentException
{
int[] counts = new int[4];
if (DNASequence != null)
{
for (int i = 0; i < DNASequence.length(); i++)
{
switch (DNASequence.charAt(i))
{
case 'A':
counts[0]++;
break;
case 'T':
counts[1]++;
break;
case 'C':
counts[2]++;
break;
case 'G':
counts[3]++;
break;
default:
throw new IllegalArgumentException("DNA Sequences should only contain A, T, C, G charaters, found: " + DNASequence.charAt(i));
}
}
}
return counts;
}
//Method that just returns the stored sequence
public String toString()
{
return DNASequence;
}
private char NucleotideBaseCount(char BaseCount){//Method to count bases
return 'a'; // replace with real implementation
}
private boolean isSubsequenceOf(String DNAStrand)
{
return false; // repalce with real implementation
}
}
Related
// Line in Main Code
public class Assignment7 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String input;
char userChoice;
int newVal, index;
IntegerList intList = null;
printMenu();
do {
System.out.print("Please enter a command or type? ");
input = scan.nextLine();
if (input.length() != 0)
userChoice = input.charAt(0);
else
userChoice = ' ';
switch (userChoice) {
case 'a':
System.out.print("How big should the list be? ");
intList = new IntegerList(scan.nextInt());
scan.nextLine();
System.out.print("What is range of the values for each random draw? ");
intList.randomize(scan.nextInt());
scan.nextLine();
break;
case 'b':
System.out.println(intList.toStrng());
break;
The above code is part of my main code, where I get user input and as them to set the boundary conditions of the array. case 'b' asks to print out the array by calling the function in the class which should return the array as a string with 10 elements per line.
// line in class
import java.util.Arrays;
import java.util.Random;
public class IntegerList {
private int arrSize;
public IntegerList(int size) {
size = arrSize;
}
private int[] IntArray = new int[arrSize];
public void randomize (int num) {
for(int i = 0;i<IntArray.length;i++) {
IntArray[i] =(int) (Math.random()*(num+1));
}
}
public void addElement(int newVal, int index) {
for(int i = index;i<IntArray.length;i++) {
int temp = IntArray[i];
IntArray[i]=newVal;
IntArray[i+1]=temp;
if(i == IntArray.length){
increaseSize(IntArray);
}
}
}
private static void increaseSize(int[] x) {
int[] temp = new int[2*x.length];
for(int i = 0; i<x.length;i++) {
temp[i]=x[i];
}
x = temp;
}
public void removeFirst(int nextInt) {
// TODO Auto-generated method stub
}
public String range() {
// TODO Auto-generated method stub
return null;
}
public String toStrng() {
String arrayOut = " ";
for(int i = 0; i<IntArray.length; i++ ) {
if(i%10 == 0 ) {
arrayOut+="\n";
}
arrayOut += IntArray[i] + " " ;
}
return arrayOut;
}
}
I'm trying to convert the array into a string and then return int and have it display 10 elements per line. I'm pretty sure I have the logic right, however, when I run the code, it does not display the array at all. How should I go about fixing this?
Look at how you are creating your array of integers through your current constructor...
public IntegerList(int size) {
size = arrSize;
}
private int[] IntArray = new int[arrSize];
When you call
intList = new IntegerList(scan.nextInt());
in your menu program, your array list won't magically know it needs to be re-initialized. It will be 0 since the value of arrSize is always 0 when you create your IntegerList object. Furthermore you have the assignment of the variables switched. Change your constructor to the following
private int[] IntArray = null;
public IntegerList(int size) {
arrSize = size;
IntArray = new int[arrSize];
}
Everything seems to work because the size of your array was always 0 and your methods just return.
You did not initialize your arrSize
You can modify your constructor to initialize arrSize
public IntegerList(int size) {
arrSize = size;
}
Also, in you toStrng method, you can just make use of arrSize instead of IntArray.length
import java.util.*;
public class Student
{
static CollegeCourse[] theirCourses = new CollegeCourse[5];
public static void main(String[] args)
{
int ID;
Scanner input = new Scanner(System.in);
/////////////////////////////////////////////////// Assigns student ID
System.out.println("Please enter your student ID >>");
ID = input.nextInt();
///////////////////////////////////////////// Wasn't sure how to populate the array
theirCourses[0] = new CollegeCourse("CIS 110", 3, 'A');
theirCourses[1] = new CollegeCourse("MATH 330", 2, 'A');
theirCourses[2] = new CollegeCourse("FR ENG 110", 2, 'A');
theirCourses[3] = new CollegeCourse("PHYSICS 110", 1, 'B');
theirCourses[4] = new CollegeCourse("GAMING 110", 1, 'C');
theirCourses[0].setCID("CIS 110");
theirCourses[1].setCID("MATH 330");
theirCourses[2].setCID("FR ENG 110");
theirCourses[3].setCID("PHYSICS 110");
theirCourses[4].setCID("GAMING 110");
theirCourses[0].setHours(3);
theirCourses[1].setHours(2);
theirCourses[2].setHours(2);
theirCourses[3].setHours(1);
theirCourses[4].setHours(1);
theirCourses[0].setGrade('A');
theirCourses[1].setGrade('A');
theirCourses[2].setGrade('A');
theirCourses[3].setGrade('B');
theirCourses[4].setGrade('C');
////////////////////////////////////////////////////////////////// Displays all preset populated courses
System.out.println("Please enter a number for the course you would to view, 0-4.\n"
+ "Courses are:");
for(int x = 0; x < theirCourses.length; ++ x)
{
System.out.println(theirCourses[x].getCID());
}
}
}
If I don't have the repetitious statements populating the array below where I already assign the array theirCourses a String, int, and char all in one line then when I get to the bottom where I have the print statement: System.out.println(theirCourses[x].getCID()); I keep getting a null output. Any clue as to what may be the cause of that? I will post the client class as well.
public class CollegeCourse
{
private String cID;
private int cHours;
private char grade;
public CollegeCourse(String string, int i, char c)
{
}
public void setCID(String c)
{
cID = c;
}
public String getCID()
{
return cID;
}
public void setHours(int h)
{
cHours = h;
}
public int getHours()
{
return cHours;
}
public void setGrade(char g)
{
grade = g;
}
public char getGrade()
{
return grade;
}
}
Like #JB Nizet mentioned, your constructor is not doing anything. Constructor is taking the parameters, set them as the value.
public CollegeCourse(String string, int i, char c) {
cID = string;
cHours = i;
grade = c;
}
Get rid of all the setCID, setHours and setGrade. That's 15 lines of unnecessary code.
package dspermutation;
import java.util.Scanner;
public class DSPermutation {
String s;
char[] c;
int n;
public static void main(String[] args) {
DSPermutation ds=new DSPermutation();
ds.input();
}
private void input() {
Scanner sc=new Scanner(System.in);
System.out.println("Enter the string");
s=sc.next();
c=s.toCharArray();
n=c.length;
permutation(c,n-1,0);
}
private void permutation(char[] cc,int nn,int ii) {
if(ii==nn)
{
System.out.println(cc);
}
else
{
for(int j=ii;j<=nn;j++)
{
swap(cc[ii],cc[j]);
permutation(cc,nn,ii+1);
swap(cc[ii],cc[j]);
}
}
}
private void swap(char p, char c0) {
int x=s.indexOf(p);
int y=s.indexOf(c0);
/*1*/ char temp=c[x];
/*2*/c[x]=c[y];
/*3*/c[y]=temp;
/*c[x]=c0;
c[y]=p;*/
}
}
The above program is for printing all permutations of a given string.The result is coming true but in swap() method if i replace line 1,2,3(written in comment) by logic written in comment(after line 1,2,3) then answer comes wrong. Why could this be happening?
Your mistake is assuming c[x] == p and c[y] == c0. But the indexes x and y are derived from the immutable string s, which doesn't reflect the values in c in its shuffled state.
You are swapping values of character array using immutable string's position (i.e String always holds the same initial values). To make your commented code work you have to add this s = String.valueOf(c);at the end of swap function.
private void swap(char p, char c0) {
int x = s.indexOf(p);
int y = s.indexOf(c0);
// char temp = c[x];
// c[x] = c[y];
// c[y] = temp;
c[y] = p;
c[x] = c0;
s = String.valueOf(c);
}
Hi I am having trouble with Scanner to get user input two separate ArrayList. When I run this code I get an IndexOutOfBounds exception after entering the two arrays.
The code adds two binary numbers together using logic of a ripple adder. An example of intended user input would be
Enter A array: 1 0 1 0
Enter B Array: 0 0 0 1
producing: 1 0 1 1
The code works when arrays are hard coded, how can I get the user to enter the arrays?
Code is shown below
import java.util.*;
public class AdderApp {
public static void main(String[] args) {
Scanner inputA = new Scanner(System.in);
ArrayList<Integer> aList = new ArrayList<Integer>();
ArrayList<Integer> bList = new ArrayList<Integer>();
int c = 0;
System.out.println("Enter A array");
aList.add(inputA.nextInt());
Scanner inputB = new Scanner(System.in);
System.out.println("Enter B array");
bList.add(inputB.nextInt());
Adder bit1 = new Adder(parseInput(aList.get(3)), parseInput(bList.get(3)), parseInput(c));
Adder bit2 = new Adder(parseInput(aList.get(2)), parseInput(bList.get(2)), bit1.getCout());
Adder bit3 = new Adder(parseInput(aList.get(1)), parseInput(bList.get(1)), bit2.getCout());
Adder bit4 = new Adder(parseInput(aList.get(0)), parseInput(bList.get(0)), bit3.getCout());
if (bit4.getCout() == false) {
System.out.println(bit4.toString() + " " + bit3.toString() + " " + bit2.toString() + " " + bit1.toString());
} else {
System.out.println("overflow!");
}
}
public static boolean parseInput(int i) {
if (i == 1) {
return true;
} else {
return false;
}
}
}
Code for Adder class:
public class Adder {
private boolean a, b, cin, cout, s;
/**
* Full Adder contructor
*/
public Adder(boolean a, boolean b, boolean cin) {
this.a = a;
this.b = b;
this.cin = cin;
s = nand(nand(a, b), cin); //sum bit
cout = or(and(nand(a, b), cin), and(a, b)); // - carry bit
}
/** Half adder constructor */
// public Adder (bloolean a, boolean b) {
//
// this.a = a;
// this.b = b;
//
// s =
//}
/**
* NAND gate
*/
public boolean nand(boolean a, boolean b) {
return a ^ b;
}
/**
* AND gate
*/
public boolean and(boolean a, boolean b) {
return a && b;
}
/**
* OR gate
*/
public boolean or(boolean a, boolean b) {
return a || b;
}
public boolean getCout() {
return cout;
}
public String toString() {
if (s == true) {
return "1";
} else {
return "0";
}
}
public String toStringCout() {
if (cout == true) {
return "1";
} else {
return "0";
}
}
}
Your entire AdderApp class can be simplified and improved to accept any bit length by accepting the input in a slightly different way and then using a for loop to add each bit. The parseInput function can be replaced with a simple boolean comparison:
import java.util.*;
public class AdderApp {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Enter A array");
char[] aIn = input.nextLine().replace(" ", "").toCharArray();
System.out.println("Enter B array");
char[] bIn = input.nextLine().replace(" ", "").toCharArray();
StringBuilder result = new StringBuilder();
Adder bit = new Adder(false, false, false);
for (int i = aIn.length - 1; i >= 0; --i) {
bit = new Adder((aIn[i] == '1'), (bIn[i] == '1'), bit.getCout());
result.append(bit + " ");
}
System.out.println(bit.getCout() ? "overflow!" : result.reverse());
}
}
Scanner.nextInt gets the next integer in the input, and then stops. Each of your lists only contains 1 element.
Use something along these lines instead:
String[] input = inputA.nextLine().split(" ");
for (String s : input)
{
try { aList.add(Integer.parseInt(s)); }
catch(NumberFormatException nfe) { /* handle exception as desired */ }
}
Alternatively, you should be able to use something like:
while (inputA.hasNextInt())
{
aList.add(inputA.nextInt());
}
You should be having a for loop to have an input into your ArrayList.
System.out.println("Enter A array");
for (int i = 0; i < 4; i++) {
aList.add(inputA.nextInt());
}
Scanner inputB = new Scanner(System.in);
System.out.println("Enter B array");
for (int i = 0; i < 4; i++) {
bList.add(inputB.nextInt());
}
The user should input 4 numbers, your one just allow the user to enter 1 number:
int count = 0;
Scanner inputA = new Scanner(System.in);
System.out.println("Enter A array");
while(count < 4){
count++;
aList.add(inputA.nextInt());
}
count = 0;
Scanner inputB = new Scanner(System.in);
System.out.println("Enter B array");
while(count < 4){
count++;
bList.add(inputB.nextInt());
}
If you want to use hasNextInt():
while(inputA.hasNextInt()){
count ++;
aList.add(inputA.nextInt());
if(count == 4){
count = 0;
break;
}
}
This question already has answers here:
Converting Roman Numerals To Decimal
(30 answers)
Closed 9 years ago.
Trying to write program to read in a string of characters that represent a Roman numeral (from user input) and then convert it to Arabic form (an integer). For instance, I = 1, V = 5, X = 10 etc.
Basically, the constructor that takes a parameter of type String must interpret the string (from user input) as a Roman numeral and convert it to the corresponding int value.
Is there an easier way to solve this besides the below in progress (which isn't compiling as yet):
import java.util.Scanner;
public class RomInt {
String roman;
int val;
void assign(String k)
{
roman=k;
}
private class Literal
{
public char literal;
public int value;
public Literal(char literal, int value)
{
this.literal = literal;
this.value = value;
}
}
private final Literal[] ROMAN_LITERALS = new Literal[]
{
new Literal('I', 1),
new Literal('V', 5),
new Literal('X', 10),
new Literal('L', 50),
new Literal('C', 100),
new Literal('D', 500),
new Literal('M', 1000)
};
public int getVal(String s) {
int holdValue=0;
for (int j = 0; j < ROMAN_LITERALS.length; j++)
{
if (s.charAt(0)==ROMAN_LITERALS[j].literal)
{
holdValue=ROMAN_LITERALS[j].value;
break;
} //if()
}//for()
return holdValue;
} //getVal()
public int count()
{
int count=0;
int countA=0;
int countB=0;
int lastPosition = 0;
for(int i = 0 ; i < roman.length(); i++)
{
String s1 = roman.substring(i,i+1);
int a=getVal(s1);
countA+=a;
}
for(int j=1;j<roman.length();j++)
{
String s2= roman.substring(j,j+1);
String s3= roman.substring(j-1,j);
int b=getVal(s2);
int c=getVal(s3);
if(b>c)
{
countB+=c;
}
}
count=countA-(2*countB);
return count;
}
void disp()
{
int result=count();
System.out.println("Integer equivalent of "+roman+" = " +result);
}
public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);
System.out.print("Please enter Roman Symbol:");
String s = keyboard.nextLine();
RomInt();
}
}
Roman numerals/Decode Example:
class Roman {
private static int decodeSingle(char letter) {
switch (letter) {
case 'M':
return 1000;
case 'D':
return 500;
case 'C':
return 100;
case 'L':
return 50;
case 'X':
return 10;
case 'V':
return 5;
case 'I':
return 1;
default:
return 0;
}
}
public static int decode(String roman) {
int result = 0;
String uRoman = roman.toUpperCase(); //case-insensitive
for (int i = 0; i < uRoman.length() - 1; i++) {//loop over all but the last character
if (decodeSingle(uRoman.charAt(i)) < decodeSingle(uRoman.charAt(i + 1))) {
result -= decodeSingle(uRoman.charAt(i));
} else {
result += decodeSingle(uRoman.charAt(i));
}
}
result += decodeSingle(uRoman.charAt(uRoman.length() - 1));
return result;
}
public static void main(String[] args) {
System.out.println(decode("MCMXC")); //1990
System.out.println(decode("MMVIII")); //2008
System.out.println(decode("MDCLXVI")); //1666
}
}
Use enum, for easy and simple solution. At first define the decimal equivalent weight at roman.
enum Roman{
i(1),iv(4),v(5), ix(9), x(10);
int weight;
private Roman(int weight) {
this.weight = weight;
}
};
This is the method to convert decimal to roman String.
static String decToRoman(int dec){
String roman="";
Roman[] values=Roman.values();
for (int i = values.length-1; i>=0; i--) {
while(dec>=values[i].weight){
roman+=values[i];
dec=dec-values[i].weight;
}
}
return roman;
}
You can try using a Hashmap to store the roman numerals and equivalent arabic numerals.
HashMap test = new HashMap();
test.add("I",1);
test.add("V",5);
test.add("X",10);
test.add("L",50);
test.add("C",100);
test.add("D",500);
test.add("M",1000);
//This would insert all the roman numerals as keys and their respective arabic numbers as
values.
To retrieve respective arabic numeral one the input of the user, you can use following peice of code:
Scanner sc = new Scanner(System.in);
System.out.println(one.get(sc.next().toUpperCase()));
//This would print the respective value of the selected key.This occurs in O(1) time.
Secondly,
If you only have these set of roman numerals, then you can go for simple switch case statement.
switch(sc.next().toUpperCase())
{
case 'I' :
System.out.println("1");
break;
case 'V'
System.out.println("5");
break;
.
.
.
& so on
}
Hope this helps.
How about this:
public static int convertFromRoman(String roman) {
Map<String, Integer> v = new HashMap<String, Integer>();
v.put("IV", 4);
v.put("IX", 9);
v.put("XL", 40);
v.put("CD", 400);
v.put("CM", 900);
v.put("C", 100);
v.put("M", 1000);
v.put("I", 1);
v.put("V", 5);
v.put("X", 10);
v.put("L", 50);
v.put("D", 500);
int result = 0;
for (String s : v.keySet()) {
result += countOccurrences(roman, s) * v.get(s);
roman = roman.replaceAll(s, "");
}
return result;
}
public static int countOccurrences(String main, String sub) {
return (main.length() - main.replace(sub, "").length()) / sub.length();
}
Not sure I've got all possible combinations as I'm not an expert in roman numbers. Just make sure that the once where you substract come first in the map.
Your compilation issue can be resolved with below code. But surely its not optimized one:
public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);
System.out.print("Please enter Roman Symbol:");
String s = keyboard.nextLine();
RomInt temp = new RomInt();
temp.getVal(s);
temp.assign(s);
temp.disp();
}