I have a small sample program which breaks when it reaches line 50 with "Error CS1513: } expected". It's typical, except that I counted the number of curly brackets over and over and found no error. I was told on another forum that the problem is probably my placement of the using keyword and class declarations, but I couldn't find anything wrong.
I would like to know if I'm making a mistake. This is the entire program; written with SharpDevelop if it makes any difference.
using System;
namespace Problem
{
public class ClassA
{
public static void Main(string[] args)
{
ClassB MyObject = new ClassB();
MyObject.MethodA();
}
}
public class ClassB
{
public String str_a = "";
public String str_b = "";
public String str_c = "";
public bool bool_a = false;
public int[] int_a = new int[6];
public void MethodA()
{
while (str_a == "" || str_a == null)
{
String str_a2 = Console.ReadLine();
if (str_a2 == "" || str_a2 == null)
{
}
else
{
str_a = str_a2;
}
}
while (str_c == "")
{
String str_c2 = Console.ReadLine();
if (str_c2 == "" || str_c2 == null)
{
}
else
{
str_c = str_c2;
}
}
while (bool_a == false)
{
Console.WriteLine(""); //Fails to compile, asks for ending brackets here
for (int i = 0; i < 6; i += 1)
{
int_a[i] = 0;
}
bool_a = true;
}
}
}
}
I'm pretty sure you could be a victim of UNICODE quotes.
ʺ ̋“”″＂
Try just removing the double-quote characters and typing them in your code editor.
Doh! Classic error! I had a declaration in a while loop:
while {
public int[] int_b = new int[6];
}
Sorry about that, SO. I was having one of those days...
Related
The code below is giving me the error java.util.NoSuchElementException right after I Ctrl+Z
to indicate that the user input is complete. By the looks of it seems as if it does not know how to just end one method without messing with the other scanner object.
I try the hasNext method and I ended up with an infinite loop, either way is not working. As a requirement for this assignment I need to be able to tell the user to use Ctrl+Z or D depending on the operating system. Also I need to be able to read from a text file and save the final tree to a text file please help.
/* sample input:
CSCI3320
project
personal
1 HW1
1 HW2
1 2 MSS.java
2 p1.java
*/
import java.util.Scanner;
import java.util.StringTokenizer;
public class Directory {
private static TreeNode root = new TreeNode("/", null, null);
public static void main(String[] args) {
userMenu();
System.out.println("The directory is displayed as follows:");
root.listAll(0);
}
private static void userMenu(){ //Displays users menu
Scanner userInput = new Scanner(System.in);//Scanner option
int option = 0;
do{ //I believe the problem is here since I am not using userInput.Next()
System.out.println("\n 1. add files from user inputs ");
System.out.println("\n 2. display the whole directory ");
System.out.println("\n 3. display the size of directory ");
System.out.println("\n 0. exit");
System.out.println("\n Please give a selection [0-3]: ");
option = userInput.nextInt();
switch(option){
case 1: addFileFromUser();
break;
case 2: System.out.println("The directory is displayed as follows:");
root.listAll(0);
break;
case 3: System.out.printf("The size of the directory is %d.\n", root.size());
break;
default:
break;
}
}while( option !=0);
userInput.close();
}
private static void addFileFromUser() {
System.out.println("To terminate inp1ut, type the correct end-of-file indicator ");
System.out.println("when you are prompted to enter input.");
System.out.println("On UNIX/Linux/Mac OS X type <ctrl> d");
System.out.println("On Windows type <ctrl> z");
Scanner input = new Scanner(System.in);
while (input.hasNext()) { //hasNext being used Crtl Z is required to break
addFileIntoDirectory(input); // out of the loop.
}
input.close();
}
private static void addFileIntoDirectory(Scanner input) {
String line = input.nextLine();
if (line.trim().equals("")) return;
StringTokenizer tokens = new StringTokenizer(line);
int n = tokens.countTokens() - 1;
TreeNode p = root;
while (n > 0 && p.isDirectory()) {
int a = Integer.valueOf( tokens.nextToken() );
p = p.getFirstChild();
while (a > 1 && p != null) {
p = p.getNextSibling();
a--;
}
n--;
}
String name = tokens.nextToken();
TreeNode newNode = new TreeNode(name, null, null);
if (p.getFirstChild() == null) {
p.setFirstChild(newNode);
}
else {
p = p.getFirstChild();
while (p.getNextSibling() != null) {
p = p.getNextSibling();
}
p.setNextSibling(newNode);
}
}
private static class TreeNode {
private String element;
private TreeNode firstChild;
private TreeNode nextSibling;
public TreeNode(String e, TreeNode f, TreeNode s) {
setElement(e);
setFirstChild(f);
setNextSibling(s);
}
public void listAll(int i) {
for (int k = 0; k < i; k++) {
System.out.print('\t');
}
System.out.println(getElement());
if (isDirectory()) {
TreeNode t = getFirstChild();
while (t != null) {
t.listAll(i+1);
t = t.getNextSibling();
}
}
}
public int size() {
int s = 1;
if (isDirectory()) {
TreeNode t = getFirstChild();
while (t != null) {
s += t.size();
t = t.getNextSibling();
}
}
return s;
}
public void setElement(String e) {
element = e;
}
public String getElement() {
return element;
}
public boolean isDirectory() {
return getFirstChild() != null;
}
public void setFirstChild(TreeNode f) {
firstChild = f;
}
public TreeNode getFirstChild() {
return firstChild;
}
public void setNextSibling(TreeNode s) {
nextSibling = s;
}
public TreeNode getNextSibling() {
return nextSibling;
}
}
}
Exception Details:
/*Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Scanner.java:907)
at java.util.Scanner.next(Scanner.java:1530)
at java.util.Scanner.nextInt(Scanner.java:2160)
at java.util.Scanner.nextInt(Scanner.java:2119)
at Directory.userMenu(Directory.java:36)
at Directory.main(Directory.java:21)*/
Your problem is this line:
option = userInput.nextInt(); //line 24
If you read the Javadoc, you will find that the nextInt() method can throw a NoSuchElementException if the input is exhausted. In other words, there is no next integer to get. Why is this happening in your code? Because you this line is in a loop once that first iteration completes (on the outer while loop) your initial input selection has been consumed. Since this is a homework, I am not going to write the code. But, if you remove the loop, you know this works at least once. Once you try to loop, it breaks. So I will give you these hints:
Change the do/while to a while loop.
Prompt the user once outside the loop.
Recreate the prompt and recapture the user input inside the loop.
For example, the code below can be used for the basis of your outer loop.
import java.util.Scanner;
public class GuessNumberGame {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Guess the secret number: (Hint: the secret number is 1)");
int guess = input.nextInt();
while (guess != 1) {
System.out.println("Wrong guess. Try again: ");
guess = input.nextInt();
}
System.out.println("Success");
input.close();
}
}
The reason why this works is because I don't reuse the same, exhausted, scanner input object to get the next integer. In your example, the initial input is inside the loop. The second time around, that input has already been consumed. Follow this pattern and you should be able to complete your assignment.
private string GenerateID()
{
}
private void auto()
{
AdmissionNo.Text = "A-" + GenerateID();
}
with prefix of A like below
A-0001
A-0002 and so on .
You can use below code.
private string GenerateId()
{
int lastAddedId = 8; // get this value from database
string demo = Convert.ToString(lastAddedId + 1).PadLeft(4, '0');
return demo;
// it will return 0009
}
private void Auto()
{
AdmissionNo.Text = "A-" + GenerateId();
// here it will set the text as "A-0009"
}
Look at this
public class Program
{
private static int _globalSequence;
static void Main(string[] args)
{
_globalSequence = 0;
for (int i = 0; i < 10; i++)
{
Randomize(i);
Console.WriteLine("----------------------------------------->");
}
Console.ReadLine();
}
static void Randomize(int seed)
{
Random r = new Random();
if (_globalSequence == 0) _globalSequence = r.Next();
Console.WriteLine("Random: {0}", _globalSequence);
int localSequence = Interlocked.Increment(ref _globalSequence);
Console.WriteLine("Increment: {0}, Output: {1}", _globalSequence, localSequence);
}
}
Whether it is an windows application or not is IMHO not relevant. I'd rather care about thread safety. Hence, I would use something like this:
public sealed class Sequence
{
private int value = 0;
public Sequence(string prefix)
{
this.Prefix = prefix;
}
public string Prefix { get; }
public int GetNextValue()
{
return System.Threading.Interlocked.Increment(ref this.value);
}
public string GetNextNumber()
{
return $"{this.Prefix}{this.GetNextValue():0000}";
}
}
This could easily be enhanced to use the a digit count. So the "0000" part could be dynamically specified as well.
Whenever I run this code, it works pretty smoothly, until the while loop runs through once. It will go back and ask for the name again, and then skip String b = sc.nextLine();, and print the next line, instead.
static Scanner sc = new Scanner(System.in);
static public void main(String [] argv) {
Name();
}
static public void Name() {
boolean again = false;
do
{
System.out.println("What is your name?");
String b = sc.nextLine();
System.out.println("Ah, so your name is " + b +"?\n" +
"(y//n)");
int a = getYN();
System.out.println(a + "! Good.");
again = askQuestion();
} while(again);
}
static public boolean askQuestion() {
System.out.println("Do you want to try again?");
int answer = sc.nextInt();
if (answer == 1) {
return true;
}
else {
return false;
}
}
static int getYN() {
switch (sc.nextLine().substring(0, 1).toLowerCase()) {
case "y":
return 1;
case "n":
return 0;
default:
return 2;
}
}
}
Also, I'm trying to create this program in a way that I can ask three questions (like someone's Name, Gender, and Age, maybe more like race and whatnot), and then bring all of those answers back. Like, at the very end, say, "So, your name is + name +, you are + gender +, and you are + age + years old? Yes/No." Something along those lines. I know there's a way to do it, but I don't know how to save those responses anywhere, and I can't grab them since they only occur in the instance of the method.
Don't try to scan text with nextLine() AFTER using nextInt() with the same scanner! It may cause problems. Open a scanner method for ints only...it's recommended.
You could always parse the String answer of the scanner.
Also, using scanner this way is not a good practice, you could organize questions in array an choose a loop reading for a unique scanner instantiation like this:
public class a {
private static String InputName;
private static String Sex;
private static String Age;
private static String input;
static Scanner sc ;
static public void main(String [] argv) {
Name();
}
static public void Name() {
sc = new Scanner(System.in);
String[] questions = {"Name?","Age","Sex?"};//
int a = 0;
System.out.println(questions[a]);
while (sc.hasNext()) {
input = sc.next();
setVariable(a, input);
if(input.equalsIgnoreCase("no")){
sc.close();
break;
}
else if(a>questions.length -1)
{
a = 0;
}
else{
a++;
}
if(a>questions.length -1){
System.out.println("Fine " + InputName
+ " so you are " + Age + " years old and " + Sex + "." );
Age = null;
Sex = null;
InputName = null;
System.out.println("Loop again?");
}
if(!input.equalsIgnoreCase("no") && a<questions.length){
System.out.println(questions[a]);
}
}
}
static void setVariable(int a, String Field) {
switch (a) {
case 0:
InputName = Field;
return;
case 1:
Age = Field;
return;
case 2:
Sex = Field;
return;
}
}
}
Pay attention on the global variables, wich stores your info until you set them null or empty...you could use them to the final affirmation.
Hope this helps!
Hope this helps!
I'm using drools-planner-5.4.0.CR1 and I wanna get list of broken constraints for final best solution
and also looked of examples of 5.4.0.CR1
I've implemented like in example but it returns empty list, in other words getScoreDetailList().size() is equal to 0, but solution.getScore() is equal to -54.
is there any suggestions?
public class SomeClass {
...
private volatile Solver solver;
private ScoreDirector scoreDirector;
...
public void someMethod() {
SolverFactory solverFactory = new XmlSolverFactory(SOLVER_CONFIG);
solver = solverFactory.buildSolver();
scoreDirector = solver.getScoreDirectorFactory().buildScoreDirector();
...
this.scoreDirector.setWorkingSolution(solution);
this.solver.setPlanningProblem(this.scoreDirector.getWorkingSolution());
this.solver.solve();
SomeSolution solution = (SomeSolution) solver.getBestSolution();
this.scoreDirector.setWorkingSolution(solution);
System.out.println( "Score: " + solution.getScore());
System.out.println( "getScoreDetailList size:" + getScoreDetailList().size());
}
public List<ScoreDetail> getScoreDetailList() {
if (!(scoreDirector instanceof DroolsScoreDirector)) {
return null;
}
Map<String, ScoreDetail> scoreDetailMap = new HashMap<String, ScoreDetail>();
WorkingMemory workingMemory = ((DroolsScoreDirector) scoreDirector).getWorkingMemory();
if (workingMemory == null) {
return Collections.emptyList();
}
Iterator<ConstraintOccurrence> it = (Iterator<ConstraintOccurrence>) workingMemory.iterateObjects(
new ClassObjectFilter(ConstraintOccurrence.class));
while (it.hasNext()) {
ConstraintOccurrence constraintOccurrence = it.next();
ScoreDetail scoreDetail = scoreDetailMap.get(constraintOccurrence.getRuleId());
if (scoreDetail == null) {
scoreDetail = new ScoreDetail(constraintOccurrence.getRuleId(), constraintOccurrence.getConstraintType());
scoreDetailMap.put(constraintOccurrence.getRuleId(), scoreDetail);
}
scoreDetail.addConstraintOccurrence(constraintOccurrence);
}
List<ScoreDetail> scoreDetailList = new ArrayList<ScoreDetail>(scoreDetailMap.values());
Collections.sort(scoreDetailList);
return scoreDetailList;
}
}
After
this.scoreDirector.setWorkingSolution(solution);
you forgot to call
this.scoreDirector.calculateScore();
I 'll docs about using Solver.getScoreDirectorFactory() in 5.4.0.Final.
I'm trying to find the easiest way to search a string for an array of possible strings. I know the easy way to do this for characters is to use myString.IndexOfAny(charArray). But how what if I'd like to search my string for strings and not just characters? Are there any .net tricks or methods that make this easier?
Basically, I'd like to do something like this:
string myName = "rahkim";
string[] names = new string[] {"joe","bob","chris"};
if(myName.IndexOfAny(names) >= 0)
{
//success code//
}
I know there are ways to do this with loops, etc. But I was hoping for something inherent in the framework.
You should define if you want to to find equal strings or search for a matching substring. Both ways are easy pre-LINQ and with LINQ.
string myName = "rahkim";
string[] names = new string[] { "joe", "bob", "chris" };
Equal Strings, LINQ
bool contains = names.Contains(myName);
Equal Strings, Pre-LINQ
bool contains = new List<string>(name).Contains(myName);
Substrings, LINQ
bool contains = names.Any(name => name.Contains(myName));
Substring, Pre-LINQ
bool contains = false;
foreach(string name in names)
if (name.Contains(myName))
contains = true;
If anyone else found this while trying to search for a .Net method like String.IndexOfAny(String[]), this is my solution:
C#
public int IndexOfAny(string test, string[] values)
{
int first = -1;
foreach (string item in values) {
int i = test.IndexOf(item);
if (i >= 0) {
if (first > 0) {
if (i < first) {
first = i;
}
} else {
first = i;
}
}
}
return first;
}
VB
Public Function IndexOfAny(test As String, values As String()) As Integer
Dim first As Integer = -1
For Each item As String In values
Dim i As Integer = test.IndexOf(item)
If i >= 0 Then
If first > 0 Then
If i < first Then
first = i
End If
Else
first = i
End If
End If
Next
Return first
End Function
You can do a LastIndexOfAny(String[]) by just switching the
i < first
to
i > first
You can (also) use the static IndexOf method of the Array class:
bool hasName = Array.IndexOf(names, myName) > -1;
int IndexOfAny(String[] rgs) would indeed be nice but it's nominally an O(n^2) operation. If, in your application, the set of strings rgs is large and always the same, the most efficient approach is to load them into a trie data structure once, and then use the trie repeatedly to search for them within the unknown strings given at runtime.
Here is the relevant code, adapted from a C# trie source I found on the web, attributed to "Kerry D. Wong." In my version, each string in the trie has a "payload" of generic type TValue. To use this trie to simply search for substrings, the payload could always be set to true, as illustrated with simple_trie.
The other thing I changed here is that this trie automatically adapts allow for storage of arbitrary Unicode strings. The array at each node—which characterizes a trie—adjusts its base and length to accomodate the range of Unicode characters which need to be stored at that node. This allows for case-sensitive matching, for example.
The C# 3.0 initialization syntax is handy for this trie, but enabling it requires a dummy implementation of IEnumerable in order to compile. The CLR doesn't seem to call GetEnumerator() and I suggest that you don't try to enumerate with its result either.
using System;
using System.Collections.Generic;
using System.Linq; // only used in Main()
class Program
{
// trie with payload of type <String>
static Trie<String> value_trie = new Trie<String>
{
{ "rabbit", "cute" },
{ "giraffe", "tall" },
{ "ape", "smart" },
{ "hippo", "large" },
};
// degenerate case of a trie without payload
static Trie<bool> simple_trie = new Trie<bool>
{
{ "rabbit", true },
{ "giraffe", true },
{ "ape", true },
{ "hippo", true },
};
static void Main(String[] args)
{
String s = "Once upon a time, a rabbit met an ape in the woods.";
// Retrieve payloads for words in the string.
//
// output:
// cute
// smart
foreach (String word in value_trie.AllSubstringValues(s))
Console.WriteLine(word);
// Simply test a string for any of the words in the trie.
// Note that the Any() operator ensures that the input is no longer
// traversed once a single result is found.
//
// output:
// True
Console.WriteLine(simple_trie.AllSubstringValues(s).Any(e=>e));
s = "Four score and seven years ago.";
// output:
// False
Console.WriteLine(simple_trie.AllSubstringValues(s).Any(e => e));
}
}
class TrieNode<TValue>
{
private TrieNode<TValue>[] nodes = null;
private TValue m_value = default(TValue);
private Char m_base;
public Char Base { get { return m_base; } }
public bool IsEnd { get { return !m_value.Equals(default(TValue)); } }
public TValue Value
{
get { return m_value; }
set { m_value = value; }
}
public IEnumerable<TrieNode<TValue>> Nodes { get { return nodes; } }
public TrieNode<TValue> this[char c]
{
get
{
if (nodes != null && m_base <= c && c < m_base + nodes.Length)
return nodes[c - m_base];
return null;
}
}
public TrieNode<TValue> AddChild(char c)
{
if (nodes == null)
{
m_base = c;
nodes = new TrieNode<TValue>[1];
}
else if (c >= m_base + nodes.Length)
{
Array.Resize(ref nodes, c - m_base + 1);
}
else if (c < m_base)
{
Char c_new = (Char)(m_base - c);
TrieNode<TValue>[] tmp = new TrieNode<TValue>[nodes.Length + c_new];
nodes.CopyTo(tmp, c_new);
m_base = c;
nodes = tmp;
}
TrieNode<TValue> node = nodes[c - m_base];
if (node == null)
{
node = new TrieNode<TValue>();
nodes[c - m_base] = node;
}
return node;
}
};
class Trie<TValue> : System.Collections.IEnumerable
{
private TrieNode<TValue> _root = new TrieNode<TValue>();
// This dummy enables C# 3.0 initialization syntax
public System.Collections.IEnumerator GetEnumerator()
{
return null;
}
public void Add(String s, TValue v)
{
TrieNode<TValue> node = _root;
foreach (Char c in s)
node = node.AddChild(c);
node.Value = v;
}
public bool Contains(String s)
{
TrieNode<TValue> node = _root;
foreach (Char c in s)
{
node = node[c];
if (node == null)
return false;
}
return node.IsEnd;
}
public TValue Find(String s_in)
{
TrieNode<TValue> node = _root;
foreach (Char c in s_in)
{
node = node[c];
if (node == null)
return default(TValue);
}
return node.Value;
}
public IEnumerable<TValue> FindAll(String s_in)
{
TrieNode<TValue> node = _root;
foreach (Char c in s_in)
{
node = node[c];
if (node == null)
break;
if (node.Value != null)
yield return node.Value;
}
}
public IEnumerable<TValue> AllSubstringValues(String s)
{
int i_cur = 0;
while (i_cur < s.Length)
{
TrieNode<TValue> node = _root;
int i = i_cur;
while (i < s.Length)
{
node = node[s[i]];
if (node == null)
break;
if (node.Value != null)
yield return node.Value;
i++;
}
i_cur++;
}
}
};
Here's the right syntax:
if(names.Contains(myName))
{
//success code//
}
if (names.Contains(myName))
{
//success code//
}