我这里有摩尔码编码器和解码器。我在尝试从子串中删除已经完成的部分时遇到问题
sub = encrypted.indexOf(',');
morsechar1 = encrypted.substring(0,sub);
morsechars = encrypted.substring(sub);
所以它继续前进而不是返回到第一个'，'和第一个''它会遇到。我坚持使用简单的代码，否则我会使用替换或修剪或其他任何东西。我能得到一些指示吗？
（（注意：搞砸了这个发布到Code Review，意味着在这里发布））
import java.io.*;
public class MORSE {
// Scanner object
BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));
/**
* Constructor for objects of class MORSE
* This is where the code for the morse encoder/decoder goes.
*/
public MORSE() throws IOException
//here is where all of the variables go.
{ //Starting with the morse code alphabet.
char[] letters = {
'a',
'b',
'c',
'd',
'e',
'f',
'g',
'h',
'i',
'j',
'k',
'l',
'm',
'n',
'o',
'p',
'q',
'r',
's',
't',
'u',
'v',
'w',
'x',
'y',
'z'
};
String[] morse = {
".-",
"-...",
"-.-.",
"-..",
".",
"..-.",
"--.",
"....",
"..",
".---",
"-.-",
".-..",
"--",
"-.",
"---",
".--.",
"--.-",
".-.",
"...",
"-",
"..-",
"...-",
".--",
"-..-",
"-.--",
"--.."
};
//Then the blank variables so the loops play nice.
String sentence = "";
String encrypted = "";
//variables to help decode.
String morsechar1, morsechars;
//a temporary character to hold a value.
char temp;
//and some blank numbers so that the loops play nice.
int choice = 0;
int sub = 0;
int alt = 0;
while (choice != 3) {
//Menu time!
//Here is where you ask the user their input.
System.out.println("1. Encrypt a sentence in Morse code");
System.out.println("2. Decrypt a sentence back to English");
System.out.println("3. Quit");
System.out.println("Please enter your choice (1,2,3)");
//once you have their number, you bring it to the right loop.
choice = Integer.parseInt(keyboard.readLine());
//Why am I restating this? So that the values go back to blank during the loop.
sentence = "";
encrypted = "";
if (choice == 1) {
//Here you ask the user to enter the words to encode to morse.
System.out.println("Enter the sentence you wish to turn into morse code.");
//this reads the sentence entered.
sentence = keyboard.readLine().substring(0);
//no caps
sentence = sentence.toLowerCase();
//analyze letters entered with this loop.
for (int x = 0; x < sentence.length(); x++) {
//copy letter from sentence to temp using charAt
temp = sentence.charAt(x);
//find the temp letter in the array in the same pos as the
//morse code blips it's letter equals.
for (int y = 0; y < 26; y++) {
//check if letter at position y = temp
if (temp == letters[y]) {
//then write out the sentence bit by bit.
encrypted = encrypted + morse[y];
encrypted = encrypted + ",";
}
//check if temp = space
if (temp == ' ') {
//add space where needed.
encrypted = encrypted + " ";
}
}
}
System.out.println(encrypted);
} else if (choice == 2) {
//Here they enter the morse code they have and want to encode.
System.out.println("Enter the sentence you wish to revert from Morse Code.");
//This reads the user's entry.
encrypted = keyboard.readLine().substring(0);
//This just defines the variable so the program works.
morsechar1 = "";
//here comes the tricky bit.
//This loop reads each letter and translates it.
for (int x = 0; x < sentence.length(); x++) {
/**
*Here's where my issues is. I'm trying to remove from the substring.
*The pieces I've already done, for both Alt and Morsechars.
* It doesn't want to work. At all.
*/
sub = encrypted.indexOf(',');
//This 'sub' finds the position of the comma that separates
//the morse code.
morsechar1 = encrypted.substring(0, sub);
//This goes from the first position to the comma as the
//first character
morsechars = encrypted.substring(sub++);
//This should go from the first comma to the next one...
//supposedly.
alt = encrypted.indexOf(' ');
//then this grabs the space as it did above.
//find the temp letter in the array in the same pos as the letter
//it's switching from the encrypted alphabet.
for (int y = 0; y < 26; y++) {
//check the morse letter and where in the array it is.
//Find the equal letter.
//This Morse.equals is a string command to match string.
if (morsechars.equals(morse[y])) {
//Then this grabs the equivalent letter in the alphabet.
sentence = sentence + letters[y];
}
//check if temp = space
if (alt == 1)
//alt was defined as a variable index.of earlier.
{
//insert space.
sentence = sentence + " ";
alt = 0;
}
}
}
//this prints out the decoded sentence.
System.out.println(morsechar1 + sentence);
} else if (choice == 3) {
//this ends the loop.
System.out.println("Thanks for stopping by.");
break;
} else {
//This sends them back into the loop for an incorrect entry.
System.out.println("Sorry, that wasn't a proper option. Try again.");
}
}
}
}你的for循环使用sentence.length()但sentence的长度为0，因为输入存储在encrypted中。我不明白你写的解码 - 这应该是choice == 2块的可接受的替代品。
//Here they enter the morse code they have and want to encode.
System.out.println("Enter the sentence you wish to revert from Morse Code.");
//This reads the user's entry.
encrypted = keyboard.readLine().substring(0);
//This just defines the variable so the program works.
morsechar1 = "";
//here comes the tricky bit.
//This loop reads each letter and translates it.
StringBuilder tsb = new StringBuilder();
StringBuilder sb = new StringBuilder();
String ch;
for (int x = 0; x < encrypted.length(); x++) {
if(encrypted.charAt(x) == ','){
ch = sb.toString();
sb = new StringBuilder();
for (int i = 0; i < morse.length; i++) {
if(ch.equals(morse[i])){
tsb.append(letters[i]);
}
}
} else {
sb.append(encrypted.charAt(x));
}
}
ch = sb.toString();
sb = new StringBuilder();
for (int i = 0; i < morse.length; i++) {
if(ch.equals(morse[i])){
tsb.append(letters[i]);
}
}
tsb.append(sb.toString());
//this prints out the decoded sentence.
System.out.println(tsb.toString());