Recursion - If Else Loop To Check If Operation Is Completed
Feb 2, 2014
I am currently learning recursion, and i have a query. I have a program that receives user input, and outputs the decimal input into binary form. In my recursive function, I have a if else loop to check if operation is completed.
public static int Converter(int input, int weight) {
System.out.printf("Input is now %d, weight is now %d
",input,weight);
if(input==0) {
return 0;
[Code] .....
The final return, when input finally hits zero is concatenating 0 to whatever i have this far. e.g. Decimal 10 should give 1010, but because of the "return 0", instead of getting 1010+0, i am getting 10100.
I can solve the problem by creating a variable sum,and passing along, but i am just curious why the final return 0 is giving me not a +0, but a concatenate 0.
Given a string of numbers and operator. Compute as follows:
Consider, "000293000002030403+0400293059694" is the input.
a. Separate the two operands and one operator: "000293000002030403" "+" "0400293059694"
b. On each string operand, take each digit. ADD them all. (2+9+3+2+3+4+3) + (4+2+9+3+5+9+6+9+4) The two string operands should now become two integers.
c. Lastly, perform the operation using the string operator specified on the original string. 26 + 51 = 77
I don't know why I get the sum of 52 when I use a for loop.
Here are my codes:
public class string2math { public static void main(String[] args) { String input = "000293000002030403+0400293059694"; String [] operand = input.split("+"); String firstOpera = operand[0];
When addition operation is performed on the character variables ,then it specifies actually that the ASCII values are added because the character variable stores ASCII value of the character constant ,then why after the addition the result cannot be stored inside a character variable ,why it needs to be stored in an integer variable only ,when actually the character variable stores the ASCII value then why is it an error to store the added result in an character variable.
*Write a program to simulate this airport's operation. You might assume a simulated clock that advances in one-minute intervals. For each minute, generate two random numbers: If the first in less than LandingTime /60, a "landing arrival" has occurred and is added to the landing queue, and if the second is less than TakeOffTime /60, a "takeoff arrival" has occurred and is added to the takeoff queue*.
*Next, check whether the runway is free. If it is, first check whether the landing queue is nonempty, and if so, allow the first plane to land; otherwise, consider the takeoff queue. Have the program calculate the average queue length and the average time that an airplane spends in a queue.*
I have most of the code done as you can see below:
Right now, I am stuck on the first calculation which is trying to figure out the average size of the landing queue. For some reason, as you can see at the bottom of my demo program, the average always comes out to be 0.0 and I'm not sure what's wrong.
Secondly, how to calculate the average time a plane stays inside a queue for. Write a program to simulate this airport's operation. You might assume a simulated clock that advances in one-minute intervals. For each minute, generate two random numbers: If the first in less than LandingTime /60, a "landing arrival" has occurred and is added to the landing queue, and if the second is less than TakeOffTime /60, a "takeoff arrival" has occurred and is added to the takeoff queue.
Next, check whether the runway is free. If it is, first check whether the landing queue is nonempty, and if so, allow the first plane to land; otherwise, consider the takeoff queue. Have the program calculate the average queue length and the average time that an airplane spends in a queue.
I have most of the code done as you can see below:
Right now, I am stuck on the first calculation which is trying to figure out the average size of the landing queue. For some reason, as you can see at the bottom of my demo program, the average always comes out to be 0.0 and I'm not sure what's wrong.
Secondly, how to calculate the average time a plane stays inside a queue for.
I am able to perform column operation but not able to perform row operation because i am not able to store data say a 2 matrix [][]. I need to store the data into a 2-D matrix. Here is my code:
Java Code:
import java.awt.List; import java.io.BufferedReader; import java.io.FileReader; import java.util.ArrayList; import java.util.Scanner; public class colRowRead {
Write a program to simulate the operation of a simple robot. The robot moves in four directions: Forward, backwawrd, left, and right. The job of the robot is to move items and place it in the right slots in each station. There are 8 stations plus the pickup station. Pick up station is the initial start where the robot picks the items. 8 items can be placed on each station. The nearest station must be filled before placing items on the next station. The items are marked with identification or serial numbers. The items with odd serial number go to the right and items with even number go to the eft. The last slot, number 7 is reserved for light items which are less than 80kg. The serial number is a five digit number, the MSB digit 5 indicates that the product must be placed in the fifth station which is keeping the product at 20 degree F.
I have now slowly moving on the learning Database Connectivity.Found a simple example on one site and tried to execute it, Creating a database, connecting to it and displaying the output.
I am getting trouble with recordset in displaying all the records in the badabase. It displays the very first record correctly but if I try to enclose it in while(rs.next()) loop, it generates an error message saying "Invalid operation at current cursor position".
I am trying to write a program which asks the user to enter two numbers and then do the arithmetic operation based on user's input . No compiling errors but when I run the program I keep getting "StringIndexOutOfBounds" error .
class arithmetic { public static void main(String[] args){ Scanner in = new Scanner(System.in); int ent1 = 0;
So, there's a new requirement to log which user issues what database operations. The dumb way is to pass the session object around, but I hope said dumb way is not the only way to achieve this. Hopefully there's another cleaner and smarter way to do this.
Whenever i perform any operation in my application Live Bytes of a particular Instance of a class increases by 1000.Although i perform the same operation everytime it always increases by 100 or 1000.Is this a memory leak or does these instances increase everytime we perform an operation.
I am somewhat of a java newbie (learned it awhile back and just getting back to programming some again.) I have a text file of data much larger than this, but here are the first ten rows and first 10 columns.
I can read and write all the data back out to files. But I am not sure about a few things.
First would it be best to use BufferedReader and OutputStream such as:
public static void main(String[] args) throws IOException { BufferedReader bReader = new BufferedReader(new FileReader ("testdata.txt")); BufferedOutputStream bytesOut = new BufferedOutputStream(new FileOutputStream ("outfile.txt"));
Second, I was then going to initialize an array but I might have 30 or more columns of data, of which I might perform and output only 10 columns to my output.txt file so is this a good way?
Third, I only want to perform operations (such as average the data, convert units or multiply two columns together) on 10 of the 30 plus columns and print out results to output.txt file. For example, In testdata.txt file above, I want to skip first seven columns. I then want to take column 8 and multiply by 100 then divide by 3 and output result to output file. I want to do same for column 9. Column 10 I want to multiply by different number (by 3.5).
I have deduct a number of days excluding holiday and weekends .So if I have to deduct 4 days from current day (02/12) and assuming 02/10 is a holiday my answer will be 02/05
Now below is the code I have come up with however its not working with the hardcoded dates I am passing in to the Holiday Calendar String .Only the last value is considered . How I should store this values and compare with the date
package date_calculation;
/** * Returns a tick for each of * the dates as represented by the <code>dtConstants</code> or the list of <code>dtDateTimes</code> * occurring in the period as represented by begin -> end. *
@MappedSuperclass public abstract class BssStandardEntityLaravel extends BssStandardEntity implements InterfacciaBssStandardEntity, Cloneable{ private static final long serialVersionUID = 1L; @Column(name = "created_at", nullable=true) @Temporal(TemporalType.TIMESTAMP) protected Date created_at = new Date();
[Code] ....
When i try to read some data with a JPA controller, this error is raised:
Persistent class "com.bss.libbssabstract.database.entity.BssStandardEntityLaravel" has no table in the database, but the operation requires it. Please check the specification of the MetaData for this class. org.datanucleus.store.rdbms.exceptions.NoTableManagedException: Persistent class "com.bss.libbssabstract.database.entity.BssStandardEntityLaravel" has no table in the database, but the operation requires it. Please check the specification of the MetaData for this class. at org.datanucleus.store.rdbms.RDBMSStoreManager.getDatastoreClass(RDBMSStoreManager.java:702)
[Code] ....
It requires BssStandardEntityLaravel table like a normal entity. I used the same entity package in other applications and it works perfectly. Why this error is raised?
I am trying to make a game, for some reason i have begun to get a java.lang.StackOverflowError.
I am not exactly sure how i can fix it. only removing line 14 from infopannel1 (and everything that used that class.) seems to work. im not sure what else i can do to fix it. or why its resulting in stack overflow for that matter.
I am putting in a link for the files i wrote this using bluej (several classes have no relevance, errorv2, demonstration, folderreadertest, ReadWithScanner, saveloadtest, menutest,rannum, and menutestTester. are all irrelivent to my problem.)
How to add the sum of an array with a recursion, but I don't understand how to use recursion. I just understand that it calls back the method. I am nearly done with the code.
import java.util.Scanner; class Question1{ public static void main(String[]args){ Scanner s = new Scanner(System.in); int size, sum; System.out.println("Please input how many numbers will be used"); size=s.nextInt();
public void myFunc(MyNode n, ArrayList<MyNode> path) { boolean hasChildren = false; path.add(n); int index = path.indexOf(n); ArrayList<MyNode> statefulPath = new ArrayList<MyNode>();
[Code] ....
I have similar code that I stepped through in a debugger. After running the code I found that it built the desired tree, in this case a root node H with left child L and right child P. I want list of lists to contain all paths from root to leaf. I expected [H, L] and [H, P]. I discovered that statefulPath is not stateful; after a recursive stack frame pops, statefulPath still contains n! But that stack frame just popped! I expected to see statefulPath be [H] in the debugger and it was [H, L]! So I later have a list [H,L,P] which I don't want. How do I make the statefulPath list I want for my algorithm?
I have a question related to the code below, that I do not understand. The aim is to count all files and subdirectories in an ArrayList full of files and subdirectories. So I have to count every file and every subdirectory.
The code concerning counting files is clear to me - every time d is of the type file I have to increment n by one. However I thought that I have to do the same thing in case d is a directory, so I would have written the same code for directories.
So what does "n += ((Directory) d).countAllFiles();" mean? In my understanding the method countAllFiles() is applied again on the object Directory ( as Directory is the class that contains this method), but how is n incremented by this? I thought n should be incremented by one as we did with files.
public int countAllFiles() { int n = 0; for(SystemFile d : content) { if(d instanceof File) { n++;
How the recursion works. I tried to figure out writing down low, mid, high at each recursive call. But I seem to be making a mistake somehow. I don't understand where the values are returned to in
I just started studying recursion and I wanted to know how to create a palindrome number going up from 1 to n then back to 1 like this: "12345...n...54321".
I've done one going downwards and then upwards like this: "n...4321234...n".
Here's my code:
Java Code: import java.util.*; public class PalindromeTest { public static void downPalindrome(int n)
The program I'm working on is supposed to read input from a file and using recursion, print the pattern of asterisks for each value until the value is either < 0 or > 25.For example, if the value was 4, the pattern would look like this
* * * * * * * * * * * * * * * *
The values are stored in a file entitled prog3.dat which looks like this
4 3 15 26 0
I've never used recursion before and haven't been able to find anything showing how it would work with this particular type of problem.Here is what I've been able to come up with so far, but I'm having problems still which I will show following the code.
import java.util.Scanner; import java.io.*; public class Program3 { public static void main(String[] args) throws Exception { int num = 0; java.io.File file = new java.io.File("../instr/prog3.dat"); Scanner fin = new Scanner(file);
[code]...
It appears to be reading the file correctly, but is only printing the top half of the pattern. Also, like I said, I'm not very familiar with recursion, so am not sure if this is actually recursion?
