I've been trying and trying and there is no way.
I want to spend a lowercase letter to uppercase equivalent.
I know and know how to use the method toUpperCase () but I want to do without it.
This is my failing code:
import java.util.Scanner;
public class ConvertLetters {
public static void main(String[] args) {
Scanner stdin = new Scanner(System.in);
System.out.print("enter a lower case letter");
char letter = stdin.nextLine();
int letter2 = 'A' + (letter - 'a');
System.out.println("and we will refund your letter capitalized");
System.out.print("Your letter: " + letter);
System.out.print("upper case equates to:");
System.out.print(letter2);
}
}
You want to finish with a char
char letter = stdin.nextLine().charAt(0);
char letter2 = (char) ('A' + (letter - 'a'));
or
char letter2 = (char) (letter - 32);
I see two problems with this code. First, you assign nextLine(), which is a string. You may want something like
char letter = stdin.nextLine().charAt(0);
instead. Second, you print int, try
System.out.print((char)letter2);
With these changes, I think your code will give you better results.
Naturally, that won't work for non-ascii characters, anyway.
Related
I'm trying to make a program where it asks for a letter from the alphabet. Lets say I choose the letter "b". The "b" should be shown in quotation marks in the program. I'm trying to learn Java, I know HTML and CSS, but Java is new to me, so go easy.
So in practice:
Choose a letter:
d
abc"d"efghijklmnopqrstuvwxyz
I've figured out how to print the alphabet
import java.util.Scanner;
public class Characters {
public static void main(String[] args) {
char c;
for(c = 'a'; c <= 'z'; ++c)
System.out.print(c + " ");
}
}
(I have added scanner, because I'll ask the user for the letter)
A very concise example:
import java.util.Scanner;
public class Main{
public static void main(String[] args){
Scanner s = new Scanner(System.in);
char c = s.next().charAt(0);
for(char i = 'a'; i < 'z'; i++){
System.out.print(i == c ? "\""+c+"\"" : i);
}
}
}
Use java.util.Scanner's .next() to read the next word, then get the first character of the word.
Sample Run:
a
"a"bcdefghijklmnopqrstuvwxy
Since Java recognises quotation marks for text, you need to add a \ before each caracter to indicate to java that you wish for it to be part of the text. For example, if you want to show "b" with quotation mark, your final string is going to be a\"b\"cdefghijklmnopqrstuvwxyz
First, we would have to read the input char:
Scanner scanner = new Scanner(System.in);
char c = scanner.next().charAt(0); // Get char
Then, I would make sure that our char is in the alphabet:
if(!('a' <= c && c <='z')) {
return; // NOT IN ALPHABET
}
If we got this far, we successfully read a character, which is in the alphabet.
Now, we can print out the modified alphabet.
for(char letter = 'a'; letter <= 'z'; letter++) {
if(letter == c) {
System.out.print("\"" + c + "\"");
}else {
System.out.print(letter);
}
}
I need to write a method nextCharacters that asks the user to input a character. The program should respond by printing the next two characters. For example, if the user enters the character e, the program should respond by printing fg to the console. You can assume that the character entered is not a whitespace character.
So far I have managed to get this way around it. Is there a more efficient way to do it? Also why can't I simply increment by doing firstChar++ and firstChar+=2;
public static void nextCharacters() {
Scanner input = new Scanner(System.in);
System.out.println("Please enter a character: ");
String first = input.next();
char firstChar = first.charAt(0);
char secondChar = (char) (firstChar + 1);
char thirdChar = (char) (firstChar + 2);
System.out.println("" + secondChar + thirdChar);
}
I'm learning Java with the book: Java. A begginer's guide.
The book shows the following example:
// Guess the letter game, 4th version.
class Guess4 {
public static void main (String args[])
throws java.io.IOException {
char ch, ignore, answer = 'K';
do {
System.out.println ("I'm thinking of a letter between A and Z.");
System.out.print ("Can you guess it: ");
// read a character
ch = (char) System.in.read();
// discard any characters in the input buffer
do {
ignore = (char) System.in.read();
} while (ignore != '\n');
if ( ch == answer) System.out.println ("** Right **");
else {
System.out.print ("...Sorry, you're ");
if (ch < answer) System.out.println ("too low");
else System.out.println ("too high");
System.out.println ("Try again!\n");
}
} while (answer != ch);
}
}
Here is a sample run:
I'm thinking of a letter between A and Z.
Can you guess it: a
...Sorry, you're too high
Try again!
I'm thinking of a letter between A and Z.
Can you guess it: europa
...Sorry, you're too high
Try again!
I'm thinking of a letter between A and Z.
Can you guess it: J
...Sorry, you're too low
Try again!
I'm thinking of a letter between A and Z.
Can you guess it:
I think the output of the program should be:
I'm thinking of a letter between A and Z.
Can you guess it: a...Sorry, you're too high
Try again!
Without a \n between 'a' and '...Sorry, you are too high'. I don't know why apears a new line. The do-while erases it.
Thank you.
ch = (char) System.in.read();
actually reads a single character.
if the input is - a\n only the first character is read and stored in ch. which is a in this case.
do {
ignore = (char) System.in.read();
} while (ignore != '\n');
This is used to remove any unwanted characters.
Why did they use this?
We just need a single letter.
So if the user had given an input which is not a single character, like "example" and if your code didn't have the loop check.
First the ch becomes e, then x ....so on.
Even without the user entering a alphabet the previous input is considered to be entered.
what if only Enter(\n) was pressed
As even \n is considered a character it is also read. In the comparison the ASCII value of it is considered.
Have a look at this question. In which a user didn't check for the unnecessary characters and got an unexpected output.
Instead doing stuff char-by-char, you could easily utilize a Scanner:
replace
// read a character
ch = (char) System.in.read();
// discard any characters in the input buffer
do {
ignore = (char) System.in.read();
} while (ignore != '\n');
with
Scanner in = new Scanner(System.in); //outside your loop
while(true) {
String input = in.nextLine();
if(!input.isEmpty()) {
ch = input.charAt(0);
break;
}
}
this program expects a capital letter from user input. The input is saved in char variable c, after that converted to ascii, and then checked, if it really is a capital letter. When not, program should ask again. Problem ist, that command System.out.println("Write capital letter: ") is executed multiple times and it looks like that:
Write capital letter:
Write capital letter:
Write capital letter:
Write capital letter:
Write capital letter:
I want to have only one "Write capital letter: " on screen after every wrong input, and it needs to eb done with ascii table.
Thanks in advance.
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
int ascii;
char c;
do {
System.out.println("Write capital letter: ");
c = (char) System.in.read();
ascii = (int) c;
} while (ascii < 65 || ascii > 90 );
System.out.println("Write capital letter: ");
do {
c = (char) System.in.read();
// ascii = (int) c; // not needed if you are using the isUppercase() method
if(! Character.isUppercase(c)){
System.out.println("Write capital letter: ");
}
} while (! Character.isUppercase(c) );
As long as the condition is true, whatever is defined in the do block is executed. So, move the statements you want to execute only once out of the do block.
Why are you using System.in.read() when you have a BufferedReader variable set?
This will solve your issue. I am using your BufferedReader in variable.
while (true) {
System.out.println("Write capital letter: ");
int b = 0
while ((b = in.read()) != -1){
char c = (char) c;
if (Character.isUpperCase(c)) break;
}
//Carry on...
}
I have been working on this for hours and now Im kinda stuck....please help me.
Im a complete programming handicap. All the methods work fine except the alphabet one.
It will receive two characters (either upper or lower case) and return a string composed of the range of char values given. Maintain the same case (upper or lower) that was passed in to the method. If an upper case and a lower case char (one of each) was passed to the method, convert the upper case char into lower case and use the lower case range. Note, the range will be inclusive of the starting char and exclusive of the ending char. Also, observe that if the starting (first) char given is greater than the ending (second) char, for example 'm' and 'h', then the method will return an empty string since there are no chars in this range.
Can you give me some help on how I can do the above on the alphabet method?
import java.util.*;
class CharacterOperations
{
public static void run()
{
int number=1;
Scanner scanner = new Scanner(System.in);
while(number > 0)
{
System.out.println("(1) Insert 1 to change a letter from its lower case value to its upper case value");
System.out.println("(2) Insert 2 to change a letter from its upper case value to its lower case value ");
System.out.println("(3) Insert 3 for the alphabet method (range of two letters) ");
System.out.println("Enter a number (or negative to quit): ");
number = scanner.nextInt();
if (number == 1)
{
System.out.print("Enter a lower case letter: ");
String a= scanner.next();
char letter = (char) a.charAt(0);
toUpper(letter);
}
else if (number == 2)
{
System.out.print("Enter an upper case letter: ");
String a= scanner.next();
char letter = (char) a.charAt(0);
toLower(letter);
}
else if (number == 3)
{
System.out.print("Enter an upper case or lower case letter: ");
System.out.print("Enter an upper case or lower case letter: ");
String a= scanner.next();
char letter1 = (char) a.charAt(0);
String b= scanner.next();
char letter2 = (char) b.charAt(0);
alphabet(letter1, letter2);
}
}
}
public static char toUpper(char letter)
{
int rep = ((int)letter - 32);
char ltr = (char)rep;
System.out.println("The letter "+ ltr + " integer representation is: " + rep);
return (char) ((int) letter -32);
}
public static char toLower(char letter)
{
int rep = (int)(letter + 32);
char ltr = (char)rep;
System.out.println("The letter " + ltr + " integer representation is: " + rep);
return (char) ((int) letter + 32);
}
public static String alphabet( char letter1, char letter2){
int rep1 = (int)letter1;
int rep2 = (int)letter2;
char ltr1 = (char)rep1;
char ltr2 = (char)rep2;
System.out.println("The letter " + ltr1 + " integer representation is: " + rep1);
System.out.println("The letter " + ltr2 + " integer representation is: " + rep2);
}
}
Thanks!
for (char c = 'a'; c <= 'z'; c++) {
System.out.println(c);
}
it's very simple ^_^
With a char you can just ++ it to get the next char and so on.
char a = 'a';
a++; // now you have b
a++; // now you have c
Just do a while loop to go from start to end char.
Use this to first to generate a random letter. You first have to generate a random number within a certain range. Then when you get the number back and store it in a char variable, it shows it as a letter.
char letter = 0;
letter = (char) (65 + (char)(Math.random() * (90 - 65) + 1));
This answaer assumes you are just talking about standard keyboard characters from the ASCII set.
Take the ascii codes for the 2 charaters and create a loop:
StringBuilder buf = new StringBuilder();
for (int i = rep1; i <= rep2; ++i)
buf.append((char)i);
return buf.toString();
This will work as they both need to be same case...
public static String alphabet(char letter1, char letter2) {
StringBuffer out = new StringBuffer();
for (char c = letter1; c < letter2; c++) {
out.append(c);
}
return out.toString();
}
Obviously you should add some error checking and handling
Simple solution:
String str = "A"
char cr = str.charAt(0);
System.out.println((cr += 1)); //got B
public static String alphabet( char letter1, char letter2){
expects to return a String because you said public static "String"
take out the String and this should work, replace it by void if you just want to print with System.out.print. or return the string that your making
beside that my advise for going to uppercase and lowercase would have been to convert the char to a String and just use the java built in method.