Convert Uppercase Letter Input to a specific Number - java

I'm super new to programming so I would love to keep this simple. The compiler accepts my code, but when I run the program and type in for example the letter A I just get a ton of errors. I tried earlier using String letter instead of int letter, but I just got compiler errors stating I couldn't convert Strings to characters or something. I'm really confused and could use a quick explanation and fix so I can get a number back. Here's my code:
import java.util.Scanner;
import java.lang.String;
public class PhoneAlgorithm {
public static void main(String[] args){
int digit = -1;
Scanner in;
in = new Scanner(System.in);
System.out.print("Enter an uppercase letter to find out the corresponding digit on a telephone: ");
int letter;
letter = Integer.parseInt(in.next());
if (letter == 'A' || letter == 'B' || letter == 'C') {
digit = 2; }
else if (letter == 'D' || letter == 'E' || letter == 'F') {
digit = 3; }
else if (letter == 'G' || letter == 'H' || letter == 'I') {
digit = 4; }
else if (letter == 'J' || letter == 'K' || letter == 'L') {
digit = 5; }
else if (letter == 'M' || letter == 'N' || letter == 'O') {
digit = 6; }
else if (letter == 'P' || letter == 'Q' || letter == 'R' || letter == 'S') {
digit = 7; }
else if (letter == 'T' || letter == 'U' || letter == 'V') {
digit = 8; }
else if (letter == 'W' || letter == 'X' || letter == 'Y' || letter == 'Z') {
digit = 9; }
else if (letter >= 'a' && letter >= '3') {
System.out.print("You did not enter a valid uppercase letter. Try again!");
}
if (digit != -1) {
System.out.println("The corresponding digit on your telephone is: " + digit);
}
}
}

When you use parseInt(str), you will get an Exception if the parameter str cannot be converted to an integer.
You must use char, since you are comparing the input with single characters:
char letter;
letter = in.nextLine().charAt(0);
str.charAt(index) Returns the char value at the specified index.

I have modified your code, I guess this is what you are looking for..
import java.util.Scanner;
public class Try {
public static void main(String[] args) {
//declarations
char letter;
int digit=0;
// Asking the user to enterstring
System.out.println("Enter the string");
String enterString;
//creating a scanner object and reading the string
Scanner input = new Scanner(System.in);
enterString= input.next();
System.out.println("Entered string is "+enterString);
int temp=0;
for(int i=0;i<enterString.length();i++){
letter=(char)enterString.codePointAt(i);
if (letter == 'A' || letter == 'B' || letter == 'C') {
digit = digit*10+2; }
else if (letter == 'D' || letter == 'E' || letter == 'F') {
digit = digit*10+3; }
else if (letter == 'G' || letter == 'H' || letter == 'I') {
digit = digit*10+4; }
else if (letter == 'J' || letter == 'K' || letter == 'L') {
digit = digit*10+5; }
else if (letter == 'M' || letter == 'N' || letter == 'O') {
digit = digit*10+6; }
else if (letter == 'P' || letter == 'Q' || letter == 'R' || letter == 'S') {
digit = digit*10+7; }
else if (letter == 'T' || letter == 'U' || letter == 'V') {
digit = digit*10+8; }
else if (letter == 'W' || letter == 'X' || letter == 'Y' || letter == 'Z') {
digit = digit*10+9; }
else if (letter >= 'a' && letter >= '3') {
System.out.print("You did not enter a valid uppercase letter. Try again!");
}
/*if (digit != 0) {
System.out.println("The corresponding digit on your telephone is: " + digit);
}*/
}
if (digit != 0) {
System.out.println("The corresponding digit on your telephone is: " + digit);
}
}
}

Related

how i print vowels and what they are?

Everytime i input my sentence it prints out the outcome each time it goes through the loop. i assume i have to put the printlines outside the loop?
import java.util.*;
public class homework4{
public static void main(String[] args) {
//Scanner
Scanner keyBd = new Scanner(System.in);
System.out.println("Enter a sentence ");
String userIn = keyBd.nextLine();
int count = 0;
String empty= "";
//Code
for (int i = 0; i < userIn.length(); i++) {
char ch = userIn.charAt(i);
if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') {
count++;
System.out.println("There are " + count + " vowels in this string");
}
if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') {
count++;
empty += ch + " ";
System.out.println("The vowels are: " + empty);
}
}
}
}
import java.util.*;
public class homework4{
public static void main(String[] args) {
//Scanner
Scanner keyBd = new Scanner(System.in);
System.out.println("Enter a sentence ");
String userIn = keyBd.nextLine();
int count = 0;
String empty= "";
//Code
for (int i = 0; i < userIn.length(); i++) {
char ch = userIn.charAt(i);
if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') {
count++;
empty += ch + " ";
}
}
System.out.println("There are " + count + " vowels in this string");
System.out.println("The vowels are: " + empty);
}
}
No need to check condition two times. As you are updating variables (count & empty) in loop, have to print only once after exiting from loop.
you just need to move the print statement outside and put a check condition if the count is still zero then it means there were no vowels and if count is not zero you can print it.
import java.util.Scanner;
public class homework4 {
public static void main(String[] args) {
//Scanner
Scanner keyBd = new Scanner(System.in);
System.out.println("Enter a sentence ");
String userIn = keyBd.nextLine();
int count = 0;
String empty = "";
//Code
for (int i = 0; i < userIn.length(); i++) {
char ch = userIn.charAt(i);
if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') {
count++;
empty += ch + " ";
}
}
if(count == 0){
System.out.println("There are no vowels in the input string");
}else {
System.out.println("There are " + count + " vowels in this string");
System.out.println("The vowels are: " + empty);
}
}
}
You don't need to test for vowels twice? (and add to count twice), only once:-
if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U'){
count++;
empty += ch + " ";
}
And your print statement doesn't need to happen every time you find a vowel:-
for (int i = 0; i < userIn.length(); i++) {
// not in here
}
System.out.println("There are " + count + " vowels in this string\n" + "The vowels are: " + empty);
Additionally...
If statements are ugly here, where there are many conditions. A switch would be easier to read and more efficient:-
switch (ch){
case 'a': case 'A':
case 'e': case 'E':
case 'i': case 'I':
case 'o': case 'O':
case 'u': case 'U':
count++;
empty += ch + " ";
break;
}
Or move the whole condition into a method
public boolean isVowel(char c){
return (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U');
}
and use
if (isVowel(ch)){
//...
}

printing special characters from char

I'm writing a program converts letters in a phone number into their corresponding digits, and it's almost complete aside from some formatting:
import java.util.Scanner;
public class PhoneKeypad
{
public static void main (String [] args)
{
Scanner scan = new Scanner (System.in);
String number;
int currentChar;
char character;
int finalNumber;
int getNumber;
int start;
String end;
currentChar = 0;
do
{
System.out.print ("\nEnter a phone number with letters: ");
number = scan.nextLine();
number = number.toUpperCase();
while (currentChar < number.length())
{
character = number.charAt(currentChar);
finalNumber = getNumber(character);
System.out.print (finalNumber);
currentChar++;
}
System.out.print ("\n\nContinue? <y/n> ");
end = scan.next();
System.out.flush();
scan.nextLine();
currentChar = 0;
} while (!end.equalsIgnoreCase("n"));
}
public static int getNumber (char uppercaseLetter)
{
int resultChar = 0;
if (Character.isLetter(uppercaseLetter))
{
if (uppercaseLetter == 'A' || uppercaseLetter == 'B' || uppercaseLetter == 'C')
resultChar = 2;
else if (uppercaseLetter == 'D' || uppercaseLetter == 'E' || uppercaseLetter == 'F')
resultChar = 3;
else if (uppercaseLetter == 'G' || uppercaseLetter == 'H' || uppercaseLetter == 'I')
resultChar = 4;
else if (uppercaseLetter == 'J' || uppercaseLetter == 'K' || uppercaseLetter == 'L')
resultChar = 5;
else if (uppercaseLetter == 'M' || uppercaseLetter == 'N' || uppercaseLetter == 'O')
resultChar = 6;
else if (uppercaseLetter == 'P' || uppercaseLetter == 'Q' || uppercaseLetter == 'R' || uppercaseLetter == 'S')
resultChar = 7;
else if (uppercaseLetter == 'T' || uppercaseLetter == 'U' || uppercaseLetter == 'V')
resultChar = 8;
else if (uppercaseLetter == 'W' || uppercaseLetter == 'X' || uppercaseLetter == 'Y' || uppercaseLetter == 'Z')
resultChar = 9;
}
else if (Character.isDigit(uppercaseLetter))
{
resultChar = Character.getNumericValue(uppercaseLetter);
}
return resultChar;
}
}
The issue I'm having is that I need to print the phone number back out exactly as the user entered it, aside the the letters. If the user enters 1-800-flowers, the program needs to print it back out as 1-800-3569377. It's the same for any special characters - hyphens, spaces, parenthesis, etc.
And the simpler the solution, the better, as I haven't yet gotten to arrays or anything more complicated than methods.

vowel counter and display the letter

public class vowel {
public static void main(String args[])
{
String sentence;
int vowels = 0, digits = 0, blanks = 0, consonants=0;
char ch;
System.out.print("Enter a String : ");
sentence = TextIO.getln();
sentence = sentence.toLowerCase();
for(int i = 0; i < sentence.length(); i ++)
{
ch = sentence.charAt(i);
if(ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u')
vowels ++;
else if(ch =='b'|| ch == 'c' || ch == 'd'|| ch =='f' || ch =='g' ||
ch == 'h' || ch =='j' || ch =='k'|| ch =='l' || ch =='m' ||
ch == 'n' || ch =='p' || ch =='q'|| ch =='r' || ch =='s' ||
ch == 't' || ch =='v' || ch =='w'|| ch =='x' || ch =='z' ||
ch == 'y')
consonants ++;
else if(Character.isDigit(ch))
digits ++;
else if(Character.isWhitespace(ch))
blanks ++;
}
System.out.println("Vowels : " + vowels);
System.out.println("Consonants : " +consonants);
System.out.println("Digits : " + digits);
System.out.println("Blanks : " + blanks);
}
}
This program works perfectly in counting, but I wish to add on a function display the word it count
For example, input ABBCC12:
Vowels :1
Input Vowels : A
Consonants :4
Input Consonants : BBCC
Digits :2
Input Digits :12
Can I know what to do next?
Thanks in advance
It looks as though the easiest way that would fit with your current way of working would be to keep hold of a StringBuilder for each type:
vowelsStringBuilder = new StringBuilder();
and then whenever you encounter one, you add it on:
vowelsStringBuilder.append(ch);
At the end, you can then use
String vowelsString = vowelsStringBuilder.toString();
to get the final String containing all the vowels.
In fact, if you do it like this, you don't really need to count them as you go, because you can get the number of vowels at the end with vowelsString.length().

Java Comparing char values with set char values in a while loop

I need to compare char values with set char values 'g' 'c' 'a' 't'(lower and upper case), for i want only those values to be entered. I can not seem to get certain cases of my input validation working.
f in the below strings can stand for any length of string that is not characters g,c,a,t.
The string "fffffff" keeps in the loop.
The string "fgf" keeps in the loop.
However, i want the strings, "fffffg" or "gfg" to exit the loop, and they are not doing so.
The actual purpose of the exercise, to take a user input of nucleotides like g,c,a,t like the one's in DNA, and convert them into the complementary string of RNA. G is complement to C and vice versa. A is complement to U(the T is replaced with U) and vice versa.
So if the string is "gcat", the response for RNA should be "cgua".
import java.text.DecimalFormat;
import javax.swing.SwingUtilities;
import javax.swing.JOptionPane;
import java.util.Random;
//getting my feet wet, 1/13/2015, program is to take a strand of nucleotides, G C A T, for DNA and give
//the complementary RNA strand, C G U A.
public class practiceSixty {
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable() {
public void run() {
String input = null;
boolean loopControl = true;
char nucleotide;
while(loopControl == true)
{
input = JOptionPane.showInputDialog(null, " Enter the sequence of nucleotides(G,C,A and T) for DNA, no spaces ");
for(int i = 0; i < input.length(); i++)
{
nucleotide = input.charAt(i);
if(!(nucleotide == 'G' || nucleotide == 'g' || nucleotide == 'C' || nucleotide == 'c' || nucleotide == 'A' || nucleotide == 'a' || nucleotide == 'T' || nucleotide == 't' ))
{
loopControl = true;
}
else if(nucleotide == 'G' || nucleotide == 'g' || nucleotide == 'C' || nucleotide == 'c' || nucleotide == 'A' || nucleotide == 'a' || nucleotide == 'T' || nucleotide == 't' )
{
loopControl = false;
System.out.println(nucleotide);
}
}
}
JOptionPane.showMessageDialog(null, "the data you entered is " + input);
StringBuilder dna = new StringBuilder(input);
for(int i = 0; i < input.length(); i++)
{
nucleotide = input.charAt(i);
if(nucleotide == 'G' || nucleotide == 'g' )
{
dna.setCharAt(i, 'c');
}
else if( nucleotide == 'C' || nucleotide == 'c')
{
dna.setCharAt(i, 'g');
}
if(nucleotide == 'A' || nucleotide == 'a')
{
dna.setCharAt(i, 'u');
}
else if(nucleotide == 'T' || nucleotide == 't')
{
dna.setCharAt(i, 'a');
}
}
JOptionPane.showMessageDialog(null, "the DNA is , " + input + " the RNA is " + dna);
}
});
}
}
You could do your check with a single regular expression, and then just use a do/while loop to keep prompting for input until the user enters something valid.
do {
input = JOptionPane.showInputDialog(
null, " Enter the sequence of nucleotides(G,C,A and T) for DNA, no spaces ");
} while (!input.matches("[GCATgcat]+"));
The regular expression will match any input that consists of one or more letters of the 8 shown. When you don't get a match, the loop repeats.

How can I check how many consonants and vowels there are in a sentence in Java?

At the end of my loop, I am planning on displaying the number of consonants and vowels in the sentence. I was wondering if there was a more efficient way to check how many consonants and vowels are in a given sentence, rather than using an if statement and manually inputting every letter. (key refers to my Scanner which has already been initialized)
Edit: It needs to ignore digits and other special characters, so for example if I write Hello# how 1are you?. There should be 8 vowels and 6 consonants.
System.out.println("Please enter the sentence to analyze: ");
String words = key.nextLine(); //the sentence the user inputs
int c = 0; //# of consonants
int v = 0; //# of vowels
int length = words.length(); //length of sentence
int check; //goes over each letter in our sentence
for(check = 0; check < length; check++){
char a = words.charAt(check);
if(a == 'a' || a == 'A' || a == 'e' || a == 'E' || a == 'i' || a == 'I' || a == 'o'
|| a == 'O' || a == 'u' || a == 'U' || a == 'y' || a == 'Y')
v = v + 1;
else if(a == 'b' || a == 'B' || a == 'c' || a == 'C' || a == 'd' || a == 'D' || a == 'f'
|| a == 'F' || a == 'g' || a == 'G' || a == 'h' || a == 'H' || a == 'j' || a == 'J'
|| a == 'k' || a == 'K' || a == 'l' || a == 'L' || a == 'm' || a == 'M' || a == 'n'
|| a == 'N' || a == 'p' || a == 'P' || a == 'q' || a == 'Q' || a == 'r' || a == 'r'
|| a == 's' || a == 'S' || a == 't' || a == 'T' || a == 'v' || a == 'V' || a == 'w'
|| a == 'W' || a == 'x' || a == 'X' || a == 'z' || a == 'Z')
c = c + 1;
}
Use Character.isLetter(ch) to determine if the character is a vowel or a consonant, then check to see if the character in question is in the set of vowels.
One way to create the set of vowels:
Set<Character> vowels = new HashSet<Character>();
for (char ch : "aeiou".toCharArray()) {
vowels.add(ch);
}
And to increment v or c:
if (Character.isLetter(a)) {
if (vowels.contains(Character.toLowerCase(a))) {
v++;
} else {
c++;
}
}
Assuming you already have a letter (vowel or consonant, not a digit nor a symbol or anything else), then you can easily create a method to define if the letter is a vowel:
static final char[] vowels = { 'a', 'A', 'e', 'E', 'i', 'I', 'o', 'O', 'u', 'U', 'y', 'Y' };
public static boolean isVowel(char c) {
for (char vowel : vowels) {
if (c == vowel) {
return true;
}
}
return false;
}
public static boolean isConsonant(char c) {
return !isVowel(c);
}
Note that I set Y and y as vowels since seems that they are in your language. In Spanish and English, Y is a consonant (AFAIK).
You can easily check if the char is a letter or not using Character#isLetter.
So, your code would become into:
for(check = 0; check < length; check++){
char a = words.charAt(check);
if (Character.isLetter(a)) {
if (isVowel(a)) {
v++;
} else {
c++;
}
}
}
How about something like
String vowels = "aeiouyAEIOUY"; // you can declare it somewhere before loop to
// to avoid redeclaring it each time in loop
//inside loop
if ((a>='a' && a<='z') || (a>='A' && a<='Z')){ //is letter
if (vowels.indexOf(a)!=-1) //is vowel
v++;
else //is consonant
c++;
}
I am sure this can be improved upon, but I'll throw it in the ring anyways.
Remove non-characters from the sentence, lowercase it, then convert to a char array and compare it to a char array of vowels that are all lowercase.
String myText = "This is a sentence.";
int v = 0;
char[] vowels = {'a','e','i','o','u'};
char[] sentence = myText.replaceAll("[^a-zA-Z]","").toLowerCase().toCharArray();
for (char letter : sentence) {
for (char vowel : vowels) {
if (letter == vowel) {
v++;
}
}
}
System.out.println("Vowels:"+ v);
System.out.println("Consonants:" + (sentence.length -v));
One easy way would be to create 2 lists:
one contains vowels (a, e, i, o, u)
the other contains consonants
Then you iterate over each character in the Java string.
See a sample below:
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Counter {
public static void main(String[] args) {
String test = "the fox is in the woods";
test = test.toLowerCase();
List<Character> vowels = new ArrayList<Character>();
vowels.addAll(Arrays.asList(new Character[]{'a', 'e', 'i', 'o', 'u'}));
List<Character> consonants = new ArrayList<Character>();
consonants.addAll(Arrays.asList(new Character[]{'b','c','d','f','g','h','j','k','l','m','n','p','q','r','s','t','v','w','x','y','z'}));
int vcount = 0;
int ccount = 0;
for (int i = 0; i < test.length(); i++){
Character letter = test.charAt(i);
if (vowels.contains(letter)){
vcount ++;
} else if (consonants.contains(letter)){
ccount++;
}
}
System.out.println(vcount);
System.out.println(ccount);
}
}
You can do a range check to make sure it is a letter, then check if it one of the vowels:
if( ( a >= 'a' && a<= 'z' ) || ( a >= 'A' && a <= 'Z' ) )
{
// is letter
switch( a )
{
case 'a': case 'A':
case 'e': case 'E':
case 'i': case 'I':
case 'o': case 'O':
case 'U': case 'u':
++v;
break;
default: // don't list the rest of the characters since we did the check in the if statement above.
++c;
}
}
Oh, there's certainly a much more readable way to do it. Not sure if that meets the "better" definition.
As a start, I'd suggest that you encapsulate what you have into methods that you can write once and call anywhere:
package misc;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* ParseUtils get counts of vowels and consonants in sentence
* #author Michael
* #link https://stackoverflow.com/questions/24048907/how-can-i-check-how-many-consonants-and-vowels-there-are-in-a-sentence-in-java
* #since 6/4/2014 6:57 PM
*/
public class ParseUtils {
private static final String VOWEL_PATTERN_STR = "(?i)[aeiou]";
private static final Pattern VOWEL_PATTERN = Pattern.compile(VOWEL_PATTERN_STR);
private static final String CONSONANT_PATTERN_STR = "(?i)[b-df-hj-np-tv-z]";
private static final Pattern CONSONANT_PATTERN = Pattern.compile(CONSONANT_PATTERN_STR);
private ParseUtils() {}
public static void main(String[] args) {
for (String arg : args) {
System.out.println(String.format("sentence: '%s' # letters: %d # vowels: %d # consonants %d", arg, arg.length(), getNumVowels(arg), getNumConsonants(arg)));
}
}
public static int getNumVowels(String sentence) {
return getMatchCount(sentence, VOWEL_PATTERN);
}
public static int getNumConsonants(String sentence) {
return getMatchCount(sentence, CONSONANT_PATTERN);
}
private static int getMatchCount(String s, Pattern p) {
int numMatches = 0;
if ((p != null) && (s != null) && (s.trim().length() > 0)) {
Matcher m = p.matcher(s);
while (m.find()) {
++numMatches;
}
}
return numMatches;
}
}
Split the String by whitespaces and and Calculate only the number of Vowels. Then Number of consonants = Length of Sentence - No. of Vowels.
Detailed Code:
System.out.println("Please enter the sentence to analyze: ");
int v = 0;
int c = 0;
String string = key.nextLine(); //the sentence the user inputs
String[] stringArray = string.split(" ");
for(int i=0;i<stringArray.length;i++)
{
for(int j= 0; j<string.length(); j++)
{
char a = string.charAt(j);
if(a == 'a' || a == 'A' || a == 'e' || a == 'E' || a == 'i' || a == 'I' || a == 'o'
|| a == 'O' || a == 'u' || a == 'U' || a == 'y' || a == 'Y')
v = v + 1;
}
c= c+(stringArray.length)-v;
}
System.out.println("Vowels:"+v+" and Consonants:"+c);
One way to do it is to get rid of the non-letters, then vowels and consonants, and get the length of what is left:
public class CountChars {
public static final String CONSONANTS = "[BCDFGHJKLMNPQRSTVWXYZ]";
public static final String VOWELS = "[AEIOU]"; // considering Y a consonant here
public static final String NOT_LETTERS = "[\\W_0-9]";
public static void main(String[] args) {
String words = "How can I check how many consonants and vowels there are in a sentence in Java?";
String letters = words.toUpperCase().replaceAll(NOT_LETTERS, "");
System.out.println("Letters: " + letters.length());
String vowels = letters.replaceAll(CONSONANTS, "");
System.out.println("Vowels: " + vowels.length());
String consonants = letters.replaceAll(VOWELS, "");
System.out.println("Consonants: " + consonants.length());
}
}
Here is the best way of doing this:
public static void checkVowelsAndConsonants(String s){
System.out.println("Vowel Count: " + (s.length() - s.toLowerCase().replaceAll("a|e|i|o|u|", "").length()));
//Also eliminating spaces, if any for the consonant count
System.out.println("Consonant Count: " + (s.toLowerCase().replaceAll("a|e|i|o| |u", "").length()));
}

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