What am I doing wrong? When I run my program it only prints some of my string, and it does not capitalize the first letter..
public class StringTraining extends ConsoleProgram {
public void run() {
String str = "halOOlOO";
capitalize(str);
}
private String capitalize(String str){
String s = "";
char ch;
for(int i = 0;i<str.length();i++) {
ch = str.charAt(i);
if(i==0 && Character.isLowerCase(ch)) {
Character.toUpperCase(ch);
s += ch;
i++;
} else {
Character.toLowerCase(ch);
s += ch;
i++;
}
}
println(s);
return s;
}
}
You should not increment i again in the loop since it will be done automatically in the signature of the loop.
You have to assign Character.toUpperCase(ch) to the String or append it.
I'd suggest you use a StringBuilder when looping to build a String object
Correction
private static String capitalize(String str){
StringBuilder s = new StringBuilder();
char ch;
for(int i = 0;i<str.length();i++) {
ch = str.charAt(i);
if(i==0 && Character.isLowerCase(ch)) {
s.append(Character.toUpperCase(ch));
} else {
s.append(Character.toLowerCase(ch));
}
}
return s.toString();
}
Output
Halooloo
You need to assign the variable ch to the upper or lower case value:
for(int i = 0;i<str.length();i++) {
ch = str.charAt(i);
if(i==0 && Character.isLowerCase(ch)) {
ch = Character.toUpperCase(ch);
s += ch;
} else {
ch = Character.toLowerCase(ch);
s += ch;
}
}
Remove some unnecessary codes from your capitalize(String) method such as i++ and use
s += String.valueOf(Character.toUpperCase(ch)); code instead of
Character.toUpperCase(ch);
s += ch;
Complete capitalize(String) method
private static String capitalize(String str) {
String s = "";
char ch;
for (int i = 0; i < str.length(); i++) {
ch = str.charAt(i);
if (i == 0 && Character.isLowerCase(ch)) {
s += String.valueOf(Character.toUpperCase(ch));
} else {
s += String.valueOf(Character.toLowerCase(ch));
}
}
println(s);
return s;
}
toLowerCase() return a string, you need to assign it to ch.
You also need to increment your i only one time (in the for, and not in the if)
Change your capitalize(String str) method like this -
private static String capitalize(String str) {
char[] chars = str.toCharArray();
String caps = chars[0]+"";
caps = caps.toUpperCase();
String output = caps;
for(int i=1;i<chars.length;i++) {
output = output + chars[i];
}
return output;
}
Output :
HalOOlOO
Related
I'm trying to count the number of times a letter appears in a string (aabcccccaaa) and placing the number of times that it does into a new string along with the corresponding letter. The problem's that I get a StringIndexOutOfBoundsException.
I kind of have a clue why but I think it's mainly because my logic is flawed with this problem.
Am I on the right track? What am I doing wrong and how can I fix it?
For example, the output should be a2b1c5a3
Here's my code:
public class Problem {
public static void main(String []args) {
String str = "aabcccccaaa";
System.out.println(compressBad(str));
}
public static String compressBad(String str) {
int countConsecutive = 0;
String compressedString = "";
for(int i = 0; i < str.length(); i++) {
if(str.charAt(i) != str.charAt(i + 1)) {
countConsecutive++;
compressedString += "" + str.charAt(i) + countConsecutive;
countConsecutive = 0;
}
}
return compressedString;
}
}
This line str.charAt(i + 1) will read out of bounds when i is the last index, i+1 is now out of bounds.
For what it's worth, here's what I would do :
public static String compressBad(final String str) {
if (str == null || str.length() < 0) {
return "";
}
int countConsecutive = 0;
StringBuilder sb = new StringBuilder();
char previousLetter = str.charAt(0);
for (char c : str.toCharArray()) {
if (c == previousLetter) {
countConsecutive++;
} else {
sb.append(previousLetter).append(countConsecutive);
previousLetter = c;
countConsecutive = 1;
}
}
sb.append(previousLetter).append(countConsecutive);
return sb.toString();
}
I'm doing a homework task that is:
Find a unique vowel in the string that is preceded by a consonant, and this consonant is preceded by a vowel.
Example: "eeaaAOEacafu"
Result is: u
What i already did:
Main.class
public class Principal {
public static void main(String[] args) {
// TODO Auto-generated method stub
Stream str = new Stream();
str.setText("eeaaAOEacafu");
System.out.println(str.returnChar(str.getVowel()));
}
Stream.class
public class Stream {
String text;
char vowel;
public String getText() {
return texto;
}
public void setText(String text) {
this.text = text;
}
public char getVowel() {
return vowel;
}
public void setVowel(char vowel) {
this.vowel = vowel;
}
public boolean isVowel(String str) {
str = str.toLowerCase();
for(int i=0; i<str.length(); i++) {
char c = str.charAt(i);
if(c=='a' || c=='e' || c=='i' || c=='o'|| c=='u') {
return true;
} else {
return false;
}
}
return false;
}
public char returnChar(String str) {
char last;
char next;
char result = '0';
int j=1;
for(int i=0; i<str.length(); i++) {
last = str.charAt(i-1);
next = str.charAt(i+1);
j++;
if(!vogal(str.charAt(i))) {
if(vogal(last) && vogal(next)) {
result = next;
}
}
}
this.setVowel(result);
return result;
} }
This returns: String index out of range: -1
This j=1, was to fix this -1 out of range. It fix but i got new one: out of range 11 because of the next.
The thing is: I have to use pure java and no API.
Can you guys help me?
use regular expressions for the test and locating the character
[aeiouAEIOU][bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ]([aeiouAEIOU])
Use a String as a cheap map to keep track of which vowels you've already seen. Also, keep a count of how many consecutive consonants you've encountered. Then, when you hit a vowel that you haven't seen before preceded by a single consonant you've found your answer.
public static void main(String[] args)
{
String s = "eeaaAOEacafu".toLowerCase();
int consCount = 0;
String seenVowels = "";
for(int i=0; i<s.length(); i++)
{
char c = s.charAt(i);
if("aeiou".indexOf(c) >= 0)
{
if(seenVowels.indexOf(c) == -1)
{
if(consCount == 1)
{
System.out.println("Result: " + c);
break;
}
seenVowels += c;
}
consCount = 0;
}
else consCount++;
}
}
Output:
Result: u
The above works if we take 'unique' to mean that we haven't seen the vowel before. If the vowel has to be unique within the input string then things are a little more complicated. Now we have to keep track of each vowel that meets the original criteria, but remove the solution if we subsequently encounter another instance of the same vowel.
Here's some code to illustrate:
public static void main(String[] args)
{
String s = "afuxekozue".toLowerCase();
int consCount = 0;
String seenVowels = "";
String answer = "";
for(int i=0; i<s.length(); i++)
{
char c = s.charAt(i);
if("aeiou".indexOf(c) >= 0)
{
if(seenVowels.indexOf(c) == -1)
{
if(consCount == 1)
{
answer += c;
}
seenVowels += c;
}
else if(answer.indexOf(c) >= 0)
{
answer = answer.replaceAll(String.valueOf(c), "");;
}
consCount = 0;
}
else consCount++;
}
if(answer.length() > 0)
System.out.println("Result: " + answer.charAt(0));
}
Output:
Result: o
Declare a string variable for the return value, and initialize it to "".
Use a for loop to iterate over all the characters in the supplied string.
Use a conditional or switch statement to check whether the character is a vowel.
The vowels are 'a','e','i','o', and 'u', uppercase or lowercase.
If it is a vowel, do nothing, otherwise add the character to the return string.
After the loop has completed, return the string.
This is what I have so far, I'm new to this so any help would be appreciated.
public static String removeVowels(String input) {
String s = "";
int f = 0;
for(int i = 0; i < input.length(); i++){
if(c == 'a'|c == 'e'|c == 'i'|c == 'o'|c =='u' | c == 'A' | c == 'E' | c == 'I' | c == 'O' | c == 'U')
f = 1;
else{
s = s + i;
f = 0;
}
}
return s;
}
With the for loop requirement:
private static String removeVowels(String s) {
if (s == null) {
return null;
}
StringBuilder sb = new StringBuilder();
Set<Character> vowels = new HashSet<Character>();
vowels.add('a');
vowels.add('A');
vowels.add('e');
vowels.add('E');
vowels.add('i');
vowels.add('I');
vowels.add('o');
vowels.add('O');
vowels.add('u');
vowels.add('U');
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (!vowels.contains(c)) {
sb.append(c);
}
}
return sb.toString();
}
You could potentially pretty this up in a number of ways, but the above should work.
Without the for loop requirement:
public static String removeVowels(String input) {
return input.replaceAll("[aAeEiIoOuU]","");
}
public class RemoveVowels {
public static void main (String [] args) {
String str = "Hello Good Morning";
String s1 = str.replaceAll("[AEIOUaeiou]" , "");
System.out.println(s1);
}
}
I have a string "aaabbaaaavvvd", it should be compressed to a3b2a4v3d
But when I run my code it prints out b3a2v4d3
Strangely, it starts with b instead of a
public class compression {
public String compress(String str){
char chararr[] = str.toCharArray();
StringBuilder sb = new StringBuilder();
int count=1;
char previous = chararr[0];
for(int i=1; i<chararr.length; i++) {
char current = chararr[i];
if(current == previous){
count++;
} else {
sb.append(current).append(count);
count = 1;
}
previous = current;
}
System.out.println(sb.toString());
return sb.toString();
}
public static void main(String args[]){
compression test = new compression();
String str = "aaabbaaaavvvd";
test.compress(str);
}
}
Error on line:
sb.append(current).append(count);
Think about the if statement
if(current == previous){
count++;
} else {
sb.append(current).append(count);
count = 1;
}
As your code steps through each character, the if statement is only false if the current character is not equal to the last (i.e. the current character is the start of a new sequence of characters).
Stepping through one-by-one:
Index 1: previous == 'a', current == 'a', if-statement: true - increments
Index 2: previous == 'a', current == 'a', if-statement: true - increments
Index 3: previous == 'a', current == 'b', if-statement: false - prints and reset
Note how upon the third index, current is b rather than the required character a, outputting b3 as opposed to a3.
Replace the append chain with previous to fix:
if(current == previous){
count++;
} else {
sb.append(previous).append(count);
count = 1;
}
You have 3 issues:
When current == previous you should add 1 to counter and then continue
When you exit the loop - print the last char that you process
You should append the previous char - not the current sb.append(previous)
your code should look like this:
public String compress(String str){
char chararr[] = str.toCharArray();
StringBuilder sb = new StringBuilder();
int count=1;
char previous = chararr[0];
for(int i=1; i<chararr.length; i++) {
char current = chararr[i];
if(current == previous){
count++;
continue;
} else {
sb.append(previous).append(count);
count = 1;
}
previous = current;
}
sb.append(previous).append(count);
System.out.println(sb.toString());
return sb.toString();
}
This code sample works. I have changed sb.append(current) to sb.append(previous) and added a sb.append(previous).append(count) outside the for loop to account for the last character
public class compression {
public String compress(String str){
char chararr[] = str.toCharArray();
StringBuilder sb = new StringBuilder();
int count=1;
char previous = chararr[0];
for(int i=1; i<chararr.length; i++) {
char current = chararr[i];
if(current == previous){
count++;
} else {
sb.append(previous).append(count);
count = 1;
}
previous = current;
}
sb.append(previous).append(count);
System.out.println(sb.toString());
return sb.toString();
}
public static void main(String args[]){
compression test = new compression ();
String str = "aaabbaaaavvvd";
test.compress(str);
}
}
Try this:
public class Compression {
public String compress(String str) {
char chararr[] = str.toCharArray();
StringBuilder sb = new StringBuilder();
int count = 0;
char previous = chararr[0];
for (int i = 0; i < chararr.length; i++) {
char current = chararr[i];
if (current == previous) {
count++;
} else {
sb.append(previous);
if (count != 1) {
sb.append(count);
}
count = 1;
}
previous = current;
}
sb.append(previous);
if (count != 1) {
sb.append(count);
}
return sb.toString();
}
public static void main(String args[]) {
Compression test = new Compression();
System.out.println(test.compress("aaabbaaaavvvd"));
System.out.println(test.compress("aaabbaaaavvvdddd"));
}
}
Output:
a3b2a4v3d
a3b2a4v3d4
Try something like below:
public String compress(String str){
String result="";
StringBuilder sb = new StringBuilder(str);
while(sb.length() != 0){
int count = 0;
char test = sb.charAt(0);
while(sb.indexOf(test+"") != -1){
sb.deleteCharAt(sb.indexOf(test+""));
count++;
}
result=result+test+count;
}
System.out.println(result);
return sb.toString();
}
i'm trying to tokenize a string in such a way that ...
Example String
Public Static void main(String[args])
String tokenizer tokenize like
public
static
void
main
String
args
but i want to tokenize in such way
public
static
void
main
(
String
[
args
]
)
means its also print the char on which string moves to tokenized
public String[] tokenise(String str){
String progress = "";
LinkedList<String> list = new LinkedList<String>();
for(int c = 0; c < str.length(); c++){
char ch = str.charAt(c);
// Skip next char if the current char is an escape character
if(ch == '\\'){
c++;
continue;
}
// If current char is to be tokenised, add progress and char to list
if(ch == ' ' || ch == '(' || ch == ')' || ch == '[' || ch == ']'){
if(!progress.equals("")) list.add(progress);
list.add(ch+"");
progress = "";
}else{
progress += ch;
}
}
String[] result = new String[list.size()];
for(int c = 0; c < result.length; c++) result[c] = list.get(c);
return result;
}
import java.util.Scanner;
import java.util.ArrayList;
public class SOQ17
{
public Scanner scan;
public String test;
public boolean check = true;
public SOQ17()
{
System.out.print("Enter your string.\n");
scan = new Scanner(System.in);
test = scan.nextLine();
for(int i = 0; i < test.length(); i++)
{
if((test.charAt(i) >= 'A' && test.charAt(i) <= 'Z') || (test.charAt(i) >= 'a' && test.charAt(i) <= 'z'))
{
System.out.print(test.charAt(i) + "");
check = true;
}
else
{
if(check)
{
System.out.println("");
}
System.out.println(test.charAt(i));
check = false;
}
}
}
public static void main(String[] args)
{
while(true)
{
SOQ17 soq = new SOQ17();
}
}
}
Here is how mine works, it will create a new line for every thing that is not a letter. If it is a letter, however, it will simply print it out. Also, I used boolean 'check' to ensure that the proper formatting is applied when alternating back and forth between letter and not.