Develop Reference

Make second word capital in a string

I don't really know how to explain the problem. I do have a scanner imported after the package. I'm not sure if you can stack methods, and if you can I'm definitely doing it wrong.
Scanner console = new Scanner(System.in);
System.out.print("Enter your name: ");
String name = console.next();
name.trim();
name.toUpperCase(name.substring(name.charAt(name.indexOf(" "))));
System.out.println("Your name is: " + name);

Just split the String into the first word and second word based on the indexOf(" ")
Capitalize the second word using toUpperCase
Concatenate both words together using +
name = name.substring(0, name.indexOf(" ")) + name.substring(name.indexOf(" ")).toUpperCase();
Note: Not sure if you are required to handle invalid input, but this code would only work assuming a valid two-word name is entered, with a space in-between
Also, make sure to change console.next() to console.nextLine() to ensure you retrieve the entire line of input

public static void main(String[] args) {
Scanner console = new Scanner(System.in);
System.out.print("Enter your name: ");
String name = console.nextLine();
String[] words = name.split(" ");
words[1] = capitalizeWord(words[1]);
name = String.join(" ", words);
System.out.println("Your name is: " + name);
}
private static String capitalizeWord(String s) {
s = s.substring(0, 1).toUpperCase() + s.substring(1).toLowerCase();
return s;
}
At first you split the input into a String array. Then you replace the first character of the 2nd (index 1) element and join the array back to a String.
Input: john doe, Output: john Doe

String is immutable in java so if you want to "change" a Strig variable value, you need to reassign it to itself. I think a good approach to prepare more than 2 input, many people has middle name e.g.
This function split the input into parts then make the first letter uppercase then return the whole name after concat them with space.
public String capitalizeName(String name) {
String[] nameParts = name.split(" ");
for (int i = 0; i < nameParts.length; i++) {
nameParts[i] = nameParts[i].substring(0, 1).toUpperCase() + nameParts[i].substring(1);
}
return String.join(" ", nameParts);
}

String is immutable in Java.
BE SIMPLE!!!
public static void main(String... args) throws IOException {
Scanner scan = new Scanner(System.in);
System.out.print("Enter your first name and last name: ");
String firstName = upperCaseFirstLetter(scan.next().trim());
String lastName = upperCaseFirstLetter(scan.next().trim());
System.out.println("Your name first name: " + firstName);
System.out.println("Your name last name: " + lastName);
}
private static String upperCaseFirstLetter(String name) {
return Character.toUpperCase(name.charAt(0)) + name.substring(1);
}

One solution would be to make the String a String array using the split(regex)-method. It will split up a string into a String array, breaking them up at regex.
For example:
String text = "This is a text.";
String textArray = text.split(" ");
for(String element : textArray)
{
System.out.println(element);
}
will print
This
is
a
text.
If you got a String[] like that, you can choose the second String (index 1 of array) and capitalize it. You can do so in a foreach loop, for example.
String text = "This is a text.";
text = text.trim(); // if you want to trim it.
String[] textArray = text.split(" ");
String newText = "";
int index = 0;
for(String element : textArray)
{
if(index == 1)
{
element = element.toUpperCase();
}
newText = newText + element + " ";
index++;
}
System.out.println(newText);
If you want to handle errors, you can put in in a try-catch-block like this.
try
{
[Your code]
}
catch (Exception e)
{
System.out.println("An error occured.");
}
This is, of course, not a very short way to do it. However, it's easy to understand and it can handle even a string consisting of several words.

Issues with Java substring method

I wrote a program that prompts a user to input his/her full name First , middle , last. I'm attempting to break that name down into three separate pieces using the substring method by locating each white space in the string. Once each white space is found the following portion of the name is stored in a new string variable.
The issue I'm having is that the middle name is storing both middle and last because the counter isn't stopping correctly as you will see in my below code so my question is how can I fix this.
Please note, I do not want to split the string, I do not want to use a StringTokenizer, I do not want to use Arrays, I already know how to do it that way. All I need to know is how to fix my counter, what I am trying to do will work this way I'm not looking for a new way to do this; I'm only working with substring and charAt.
import java.util.Scanner;
public class Example
{
public static void main(String[] args)
{
String name = "",
firstName = "",
middleName = "",
lastName = "";
Scanner in = new Scanner(System.in);
System.out.print("Please enter your name 'First Middle Last': ");
name = in.nextLine();
int i = 0;
while(i < name.length())
{
if(name.charAt(i) == ' ')
{
firstName = name.substring(0, i); // Starts at 0 ends at first occurence of ' '
/* middleName = name.substring(i + 1, i); Should start at i + 1,
or one postion after the previously located white space and
then end at the next occurence of ' '
^ The above does not work, and this is where the issue is
happening, how ever if I do the following */
middleName = name.substring(i + 1, name.length());
/* This does work but because the endIndex is name.length() it
runs the length of name and grabs both the middle and last name.*/
i = name.length();
}
++i;
}
System.out.print("\nDisplayed with last name first: " + "\nLast Name: " + lastName + "\nFisrt Name: " + firstName + "\nMiddle Name: " + middleName);
}
}
The output this produces looks like this
Please enter your name 'First Middle Last': First Middle Last
Displayed with last name first:
Last Name:
First Name: First
Middle Name: Middle Last
As you can see first Name is displayed correctly.
Middle name is not because it included "Last" and not just "middle"

You could use indexOf(' ') and lastIndexOf(' ') to find first space and last space
everything before 1st space is firstname
everything after last space is lastname
the rest in the middle is middlename
Pseudocode:
firstName = name.substring(0, name.indexOf(' '));
middleName = name.substring(name.indexOf(' ') + 1, name.lastIndexOf(' '));
lastName = name.substring(name.lastIndexOf(' ') + 1);

Instead of substring you can use split function:
String string = "Peter Ralph Joseph"; //Here the string
String[] parts = string.split(" "); //Here the string it is divide taking as reference the space
System.out.println(parts[0]); //Peter
System.out.println(parts[1]); //Ralph
System.out.println(parts[2]); //Joseph
In my opinion, it is easier and faster to do it with split function.

Instead of running through a loop with charAt, if you really want to use substring you could just do:
int firstSpace = fullName.indexOf(' ');
String firstName = fullName.substring(0, firstSpace);
int secondSpace = fullName.indexOf(' ', firstSpace+1);
String middleName = fullName.substring(firstSpace+1, secondSpace);
String lastName = fullName.substring(secondSpace+1);

var mode = 0;
var last = 0;
for(i=0;i<name.length();i++)
{
if(name.charAt(i)==' '||i==(name.length()-1))
{
mode++;
var text = name.substring(last, i-last);
last = i+1;
if(mode==1) { firstName = text; }
else if(mode==2) { middleName = text; }
else if(mode==3) { lastName = text; break; }
}
}

do it in the following way:
no need to run the while loop.
firstName=name.substring(0,name.indexOf(' '));
middleName=name.substring(name.indexOf(' ')+1,name.lastIndexOf(' '));
lastName=name.substring(name.lastIndexOf(' ')+1,name.length());

Issue with substring method

I wrote a little program that prompts a user to enter their first middle and last name I then attempt to locate each white space and store the name that comes after the whitespace into a new String variable.
Problem: I want to locate the white spaces before each part of the name so that I can take each relative name and store it in a new String variable but i'm not sure where I'm going wrong.
import java.util.Scanner;
public class Example
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
String name = "",
firstName = "",
middleName = "",
lastName = "";
boolean isName = false;
while(!isName)
{
System.out.print("\nEnter your name as 'First Middle Last': ");
name = input.nextLine();
if(name.length() < 0)
{
System.out.print("\nEnter your name as 'First Middle Last': ");
name = input.nextLine();
System.out.print("Invalid input");
}
else isName = true;
}
for(int j = 0; j < name.length(); j++)
{
if(name.charAt(j) == ' ')
{
firstName = name.substring(0, j); // Start at 0 end at first white space
middleName = name.substring(j + 1, name.length());
lastName = name.substring(j + 1, name.length());
}
}
System.out.println("\nLast Name, First Name, Middle Name: " + lastName + firstName + middleName );
}
}
The output I'm getting looks like this
Enter your name as 'First Middle Last': Adam Thomas Smith
Last Name, First Name, Middle Name: SmithAdam ThomasSmith
Any suggestions as to how to fix this?

name = name.trim(); // To avoid suprises, as Pshemo suggested.
String[] splitName = name.split("\\s+");
System.out.println("\nLast Name, First Name, Middle Name: "
+ splitName[2] + " " + splitName[0] + " " + splitName[1]);
Try this instead. It uses String.split() to split the name on a space (\\s+, a regex) and returns the values as an array. The names could also be assigned to a variable if you choose.

You can try the following code, just by splitting the 'name' variable on each space into an String[] Then by getting each value from the array and assigning to the value you wish.
String[] str = name.split(" ");
firstName = str[0];
middleName = str[1];
lastName = str[2];

Better to use split(" ") function... It will change you string to an string array. Eg:-
String names = "Madan mohan malviya";
String arr[] = name.split(" ");
for( name :names){
System.out.println(name); // print each string content
}

Accept 5 names and print the longest name?

I want to the longest name for 5 given names. I think I should use compareTo() method or length()?
Output must be like this :
enter 5 names :
Joey
Mark
Catherine
Zachery
Foster
Longest name is Catherine.
What method should I use and how? This is my code so far:
Scanner x = new Scanner(System.in);
String name = ""
System.out.print("Enter 5 names");
name = x.nextLine();
name2 = x.nextLine();
name3 = x.nextLine();
name4 = x.nextLine();
name5 = x.nextLine();
if(name.compareTo(name2)>0) //is this method right?

.compareTo tells you which string comes first in lexicographic order (<0 if s1 < s2, 0 if s1==s2, >0 if s1>s2)
String s1 = "abc";
String s2 = "def";
s1.compareTo(s2) < 0;
.length() returns the length of a string
s1.length()==3;
In your case, you need to compare based on length, so you need the latter. If it's only 5 names, you can take the first and assume it's the longest, and then read the others one by one by keeping the "longest so far" saved and comparing them as they come. After all, you only care about the longest.
If you wanted them to be sorted by length, while still keeping them all, you'd need to store them in some sort of collection (list, array), then sort it based on length.
The problem is easy enough, so I won't provide directly the code, try to grok it yourself, you can do it :)

import java.util.Scanner;
public class LenghtyName {
public static void main(String[] args) {
Scanner x = new Scanner(System.in);
/*
Instead of declaring 5 different String variable
just use String array with size = 5
*/
String[] names = new String[5];
System.out.print("Enter 5 names :");
names[0] = x.nextLine();
names[1] = x.nextLine();
names[2] = x.nextLine();
names[4] = x.nextLine();
names[5] = x.nextLine();
//Assume lenthyName as empty String
String lengthyName = "";
/*
Iterate over String array using for-each loop
*/
for (String name : names) {
/*
-Check null to avoid NullPointerException
-Trim the left and right blank space in name by #trim()
-Compare current name length with lengthyName if greater
replace the lengthyName by current name.
*/
if (name != null && name.trim().length() > lengthyName.length()) {
lengthyName = name;
}
}
/*
Print length name
*/
System.out.println("Longest name is " + lengthyName);
}
}

What about this?
Scanner in = new Scanner(System.in);
// no need to have 5 all over the code.
// Define it once to avoid "magic nubmers"
int namesCount = 5;
// fun fact: shortest name is always "". We don't have to use null
String longestName = "";
System.out.print("Enter " + nameCount + " names:");
for (int i=0; i< nameCount; i++){
// store new name from user
String candidate = in.readLine();
// is this one longer than the current longest?
if (longestName.length() < candidate.length()){
// found a longer name
longestName = candidate;
}
}
System.out.println("Longest name is " + longestName);
This gives up storing the names, as it seems you only use the longest one anyway. It also generalizes the number of names to iterate, and most importantly the variable names are meaningful names.

Here's a solution that should work:
public class LongestWord {
public static String getLongestString(String[] array) {
int maxLength = 0;
String longestString = null;
for (String s : array) {
if (s.length() > maxLength) {
maxLength = s.length();
longestString = s;
}
}
return longestString;
}
public static void main(String[] args) {
String[] toppings = {"Cheeddddddddddse", "Pepperoni", "Black Olivesddd"};
String longestString = getLongestString(toppings);
System.out.format("longest string: '%s'\n", longestString);
}
}

An easy way would be a for loop to read 5 names and find the length for largest name. Using the for loop avoids the creation of 5 deterrent string variables.
If you want to use those names later you can go for String array.
public static void main(String[] args) throws IOException {
Scanner x = new Scanner(System.in);
String name = "";
String maxName = "";
int maxLength = 0;
System.out.println("enter 5 name :");
for (int i = 0; i < 5; i++) { // read 5 names
name = x.nextLine();
if (maxLength < name.length()) { // check longest name
maxLength = name.length();
maxName = name; // store in temp variable to show
}
}
System.out.println("Longest name is " + maxName); // print largest name
}
Output:
enter 5 name :
raj
sita
gita
mukherjee
rita
Longest name is mukherjee

Here's a solution that should work with any number of entries:
Scanner x = new Scanner(System.in);
String name = "", temp="";
while (x.hasNextLine()){
temp = x.nextLine();
if (temp.length() > name.length()) name = temp;
}
System.out.println("Longest is " + name);
You'll need to Ctrl + Z to end the inputStream on Windows

this is my code for comparing 3 input strings by their length:
public static void main(String[] args) {
String string1 , string2 , string3;
Scanner input = new Scanner(System.in);
System.out.println("Enter three string names to compare");
string1 = input.nextLine();
string2 = input.nextLine();
string3 = input.nextLine();
if (string1.length()>string2.length()) {
if (string1.length() > string3.length())
System.out.println("String 1 has the longest length , length = "+string1.length());
}
if (string2.length()>string1.length()){
if(string2.length()>string3.length())
System.out.println("String 2 has the longest length , length = "+string2.length());
}
if (string3.length()>string1.length()) {
if (string3.length() > string2.length())
System.out.println("String 3 has the longest length , length = " + string3.length());
}
}

//SIMPLE JAVA SOLUTION
class GFG
{
String longest(String names[], int n)
{
String res="";
for(int i=0;i<n;i++)
{
if(res.length()<names[i].length())
{
res=names[i];
}
}
return res;
}
}

fName.substring out of bounds

public class Registration {
public static void main(String[] args) {
final String MY_DELIMITER = "','";
boolean tryAgain = true;
String fName = "";
String A = fName.substring(0,2);
String lName = "";
int lNameLength = lName.length();
String B = lName.substring(lNameLength-4,lNameLength);
String address = "";
String zip = "";
String C = zip.substring(0,5);
String age = "";
String D = age.substring(0,1);
String gender = "";
String race = "";
String regList = "";
Scanner myScanner = new Scanner(System.in);
boolean showList = false;
// Get input from the user until they type "q"
// For each input check for "q"
// if not q, append the input
// to the existing String + the delimiter
while(tryAgain)
{
System.out.println("Name: (q to quit)");
fName = myScanner.nextLine();
System.out.println("Last Name: (q to quit)");
lName = myScanner.nextLine();
System.out.println("Addess: ");
address = myScanner.nextLine();
System.out.println("Age: ");
age = myScanner.nextLine();
System.out.println("Gender: ");
gender = myScanner.nextLine();
System.out.println("Race: ");
race = myScanner.nextLine();
if(fName.equals("q"))
{
tryAgain = false;
}
else
{
// Append new name to the list using a delimiter
regList = fName + lName + "\n" + address + "\n" + age + "\n" + gender + "\n" + race + MY_DELIMITER;
}
} // end of while( )
System.out.println("Here is your registration:" + regList);
// Convert the String into an array, using the same delimiter
String[ ] regArray = regList.split(MY_DELIMITER);
// Ask the user if they want to display the contents of the array
// If "y" then display the list using a foreach loop
System.out.println("Would you like to see the registration from the Array? [y-n]");
fName = myScanner.nextLine( );
myScanner.close();
fName = fName.toLowerCase( );
showList = fName.equals("y")?true:false;
if(showList)
{
// Display the results using for each
System.out.println("Here is your registration from the array: ");
// Use a for each statement instead of the more complex for( ) loop
// for(int counter=0; counter < employeeArray.length; counter++)
for(String thisReg:regArray)
{
System.out.println(thisReg);
System.out.printf("USER ID: ", A + "-" + B + "-" + C + "-" + D);
}
} // end of if(showList)
}
}
I am trying to extract out the first 3 letters of the fName input, so I figured I could use fName.substring to do that, but it gives me this error.
Sorry I didn't add all of my code, to save time. Apparently it looked confusing. Any way so the fName input is the name of the user. Can it not be in that order?

Erm...your sequence of operations is suspect. Everywhere, actually.
Look at the following interaction:
String fName = "";
String A = fName.substring(0,2);
You declare an empty string, then immediately take the substring of it. Where are you getting the data for the substring from? There's nothing to substring here - the empty string has a length of zero.
You should be certain that you're putting data into your string before taking a substring of it. Using a Scanner would go a long way here.
Or better yet, moving your instance of myScanner at the top of main would make it much clearer as to where that's supposed to go, and how it's supposed to work.

Always check the length of string before substring anything. Especially when a user is giving you this variable.

You are trying to get a substring of an empty string.
String fName = "";
String A = fName.substring(0,2); // here fName is empty!!!
Change fName into some actual String and also check for length of the String before calling substring to make sure substring of the size you want exists.
String fName = "somestring";
if(fName.length() >= 2) {
String A = fName.substring(0,2);
System.out.println(A); // prints out "so"
}
That is the case with all of your other Strings as well.