I tried this program but it only printed out the frequency of some letters. Could someone tell my what I did wrong? Any help would be greatly appreciated. Yours truly, Quang Pham
This is what I got in a run of the program. Welcome to the Letter Count program. Please enter some lines of text followed by a period and a return. It takes a some time to compute. . . * 1: Four score and seven years ago our forefathers * 2: brought forth upon this continent a new nation, * 3: conceived in liberty, and dedicated to the * 4: proposition that all men are created equal. Letter Frequency a 13 c 6 e 19 g 2 i 9 k 0 m 1 o 15 q 1 s 6 u 5 w 1 y 2
import java.util.Scanner ;
/**
* The Letter Counter program counts the frequency of the letters of the
* alphabet in some lines of text. After a period and a return, the computer
* displays the frequency.
*
* @author Quang Pham
* @version Module 8, Homework Project 2, 4/1/20
*
* Algorithm:
*
* 1. User enters multiple lines of text.
* 2. The program will read in the lines of text and display a list of all the
* letters that occur in the text, with the number of times the letter occurs.
* 3. The last line of input should be ended with a period, which serves as a
* sentinel value.
*
* Problem description:
* Write a program that will read in multiple lines of text from the user
* and display a list of all the letters that occur in the text, along with the
* number of times each letter occurs.
*
* The last line of input from the user should end with a period, which will
* serve as a sentinel value. Once the last line has been entered, the counts
* for all letters entered by the user should be listed in alphabetical order as
* they are output. Use an array of base type int of length 28, so that each
* indexed variable contains the count of how many letters there are. Array
* indexed variable 0 contains the number of a’s, array indexed variable 1 contains
* the number of b’s and so forth. Allow both uppercase and lowercase letters as
* input, but treat uppercase and lowercase versions of the same letter as being equal.
*
* Hints: You might find it helpful to define a "helper" method that takes a character
* as an argument and returns an int value that is the correct index for that character,
* such as ‘a’ returning 0, ‘b’ returning 1, and so forth. Note that you can use a
* typecast to change a char to an int, like (int) letter. This will not get the
* number you want, but if you subtract (int) 'a', you will then have the right index.
* Allow the user to repeat this task until the user says she or he is finished.
*
* A dialog may look something like the following
*
* Enter several lines of text to analyze. (Copy and paste to save time.) When done,
* end a line with a period and press return.
* 1: Four score and seven years ago our forefathers
* 2: brought forth upon this continent a new nation,
* 3: conceived in liberty, and dedicated to the
* 4: proposition that all men are created equal.
*
* Here's the counts of characters:
* a: 13
* b: 2
* c: 6
* d: 7
* e: 19
* f: 4
* g: 2
* h: 6
* i: 9
* l: 4
* m: 1
* n: 14
* o: 15
* p: 3
* q: 1
* r: 12
* s: 6
* t: 15
* u: 5
* v: 2
* w: 1
* y: 2
*
* Again, you can submit a single class for this project which contains your main
* method and any helper methods where you feel they can be used.
*
* Along with the file containing your program, submit three print screens or screen
* snips, each with several lines of text entered by the user, and the count for each
* character (a-z).
*/
public class LetterCounter
{
public static void main(String[] args) {
int frequency = 0 ;
char character = ' ' ;
String linesOfText = " " ;
char[] alphabet = new char[28] ; // new alphabet array
for(char ch = 'a'; ch <= 'z'; ++ch)// fills alphabet array with the alphabet
{
alphabet[ch-'a']=ch ;
}
System.out.println("Welcome to the Letter Count program.") ;
System.out.println("Please enter some lines of text followed by a period and a return.") ;
Scanner keyboard = new Scanner(System.in) ;
linesOfText = keyboard.nextLine() ;
System.out.println("Letter Frequency") ;
for (int i = 0; i < alphabet.length; i++)
{ frequency = 0 ;
for (int j = 0; j < linesOfText.length(); j++) {
character = linesOfText.charAt(j) ;
if (character == alphabet[i]) {
frequency++ ;
}
}
System.out.println(alphabet[i] + "\t\t" + frequency) ;
i++;
}
}
}
You asked what you did wrong. Well you are very close and you only did two things incorrectly.
- This line
char[] alphabet = new char[28]should be 26. - Look at the following code from your program.
for (int i = 0; i < alphabet.length; i++)
{ frequency = 0 ;
for (int j = 0; j < linesOfText.length(); j++) {
character = linesOfText.charAt(j) ;
if (character == alphabet[i]) {
frequency++ ;
}
}
System.out.println(alphabet[i] + "\t\t" + frequency) ;
i++;
}
In the first loop you increment i using i++
But you also increment it at the end after the print statement. The last one should be
removed.
A few observations
Instead of searching for your character inside an inner loop, just use the character to index into your list and bump the count. For example:
int count[] = new int[26];
say an you find the letter c =='i'.
count[c - 'a']++; ///increments the count for letter i.