I'm trying to write a program that asks the user to input the size of the array the user wants to create, and then asks the user to fill the array with elements, and then it should display the array with its elements and, ask the user to conduct a search for an integer. It should conduct a linear and binary search, while displaying how many probes it took to determine is the element is in the array. So far the only output i have gotten is that the element has not been found. If you could look at my code and see what the problem is, because i have tried for hours and i have changed everything i can think of. Any help would be greatly appreciated.
import java.util.Scanner;
public class Searching
{
public static int[] anArray = new int[100];
private int numberOfElements;
public int arraySize = numberOfElements;
public String linearSearch(int value)
{
int count = 0;
boolean valueInArray = false;
String indexOfValue = "";
System.out.print("The Value was Found in: ");
for(int i = 0; i < arraySize; i++)
{
if(anArray[i] == value)
{
valueInArray = true;
System.out.print(i + " ");
indexOfValue += i + " ";
}
count ++;
}
if(!valueInArray)
{
indexOfValue = " None found";
System.out.print(indexOfValue);
}
System.out.println("\nIt took " + count + " probes with a linear search to find");
return indexOfValue;
}
public void binarySearch(int value)
{
int min = 0;
int max = arraySize - 1;
int count = 0;
while(min <= max)
{
int mid = (max + min) / 2;
if(anArray[mid] < value) min = mid + 1;
else if(anArray[mid] > value) max = mid - 1;
else
{
System.out.println("\nFound a Match for " + value + " at Index " + mid);
min = max + 1;
}
count ++;
}
System.out.println("It took " + count + " probes with a binary search to find");
}
public static void main(String[] args)
{
#SuppressWarnings("resource")
Scanner scan = new Scanner(System.in);
System.out.println("Input the number of elements in your Array");
int numberOfElements = scan.nextInt();
if(numberOfElements <= 0)
{
System.exit(0);
}
int[] anArray = new int[numberOfElements];
System.out.println("\nEnter " + numberOfElements + " Integers");
for(int i = 0; i < anArray.length; i ++)
{
System.out.println("Int # " + (i + 1) + ": ");
anArray[i] = scan.nextInt();
}
System.out.println("\nThe integers you entered are: ");
for(int i = 0; i < anArray.length; i ++) // for loop used to print out each element on a different line
{
System.out.println(anArray[i]);
}
System.out.println("Which element would you like to find?");
int value = scan.nextInt();
Wee3Q2JOSHBALBOA newArray = new Wee3Q2JOSHBALBOA();
newArray.linearSearch(3);
newArray.binarySearch(value);
}
}
hmm I am not sure you are using an array the correct way, you see an Array is a set size and I dont think you can expand like they way you are doing...
Instead try setting the size of the array to certain length.
Or use vectors
Related
I'm creating two classes called stop watch and random numbers, which I have already done, but I needed to create a test program that would measure the execution time of sorting 100,000 numbers using selection sort. I know how to create a selection sort, I just don't know how to take the random numbers class and put it together with the selection sort, I get the error message "incompatible types random numbers cannot be converted to int" I hope someone can help me.
My random numbers class
import java.util.Random;
public class randomnumbers {
Random ran1 = new Random();
private int size;
public randomnumbers(){
size = 100000;
}
public int getSize(){
return size;
}
public void setSize(int newSize){
size = newSize;
}
public int [] createArray(int [] size){
for (int i = 0; i < size.length; i++){
size[i] = ran1.nextInt();
}
return size;
}
public static void printArray (int [] array){
for (int i = 0; i < array.length; i++){
if (i < 0){
System.out.println(array[i] + " ");
}
}
}
}
My test Program
public static void main (String [] args){
// Create a StopWatch object
StopWatch timer = new StopWatch();
//create random numbers
randomnumbers numbers = new randomnumbers();
//Create the size of the array
numbers.getSize();
// Invoke the start method in StopWatch class
timer.start();
//sort random numbers
selectionSort();
// Invoke the stop method in StopWatch class
timer.stop();
// Display the execution time
System.out.println("The execution time for sorting 100,000 " +
"numbers using selection sort: " + timer.getElapsedTime() +
" milliseconds");
}
// selectionSort performs a selection sort on an array
public static void selectionSort(int[] array) {
for (int i = 0; i < array.length - 1; i++) {
int min = array[i];
int minIndex = i;
for (int j = i + 1; j < array.length; j++) {
if (array[j] < min) {
min = array[j];
minIndex = j;
}
}
if (i != minIndex) {
array[minIndex] = array[i];
array[i] = min;
}
}
}
}
Where exactly are you getting "incompatible types random numbers cannot be converted to int" error?
There are multiple issues with the code:
Unconventional naming
size field is in randomnumbers class is used as actual array size in constructor but in createArray it's overshadowed with a parameter of the same name but different type and meaning.
You are not passing any array to selectionSort in Main. This is where I get compile error on your code.
printArray has if (i < 0) condition that is false for all ran1.nextInt() numbers so it will not print anything.
Feeding selectionSort with numbers.createArray(new int[numbers.getSize()]) compiles and ends up sorting the array.
I am having an issue with my merge sort, when I print out my sortedArray it only returns [ 0.0, 0.0.....] Im not sure if there is an error in my sort code or in my print line or if it has to do with doubles. The code I am us posted below.
By calling System.out.println(toString(sortedArray) I get an even more obscure answer.
Thanks for any help.
package mergesort;
import java.util.Arrays;
import java.util.Random;
public class mergesort {
public static void main(String[] args) {
double[] array = getIntArray();
long before = System.nanoTime();
double[] sortedArray= mergeSort(array);
System.out.println("Sorting took "+ (System.nanoTime() - before) +" nanoseconds ");
System.out.println(toString(array) + "\n\n" + toString(sortedArray) + "\n main method completed in: " + (System.nanoTime() - before) + " nanoseconds.");
}
private static String toString(double[] array) {
StringBuilder sb = new StringBuilder("[ ");
double len = array.length;
for(int i = 0; i < len - 1; i++) {
sb.append(array[i] + ", ");
}
sb.append(array[(int) (len - 1)] + " ]");
return sb.toString();
}
public static double[] mergeSort(double[] array) {
if (array.length <= 1) {
return array;
}
int half = array.length / 2;
return merge(mergeSort(Arrays.copyOfRange(array, 0, half)),
mergeSort(Arrays.copyOfRange(array, half, array.length)));
}
private static double[] merge(double[] ds, double[] ds2) {
int len1 = ds.length, len2 = ds2.length;
int totalLength = len1 + len2;
double[] result = new double[totalLength];
int counterForLeft =0,counterForRight=0,resultIndex=0;
while(counterForLeft<len1 || counterForRight < len2){
if(counterForLeft<len1 && counterForRight < len2){
if(ds[counterForLeft]<= ds2[counterForRight]){
result[resultIndex++] =(int) ds[counterForLeft++];
} else {
result[resultIndex++] =(int) ds2[counterForRight++];
}
}else if(counterForLeft<len1){
result[resultIndex++] = (int) ds[counterForLeft++];
}else if (counterForRight <len2){
result[resultIndex++] =(int) ds2[counterForRight++];
}
}
return result;
}
private static double[] getIntArray() {
double[] array = new double[10000];
Random random = new Random();
for(int i = 0; i < 10000; i++) {
array[i] = (random.nextDouble() * .99999);
}
return array;
}
}
In the merge method, when copying from one of the input arrays to the results, you cast to int. For example:
result[resultIndex++] =(int) ds[counterForLeft++];
All your doubles are in the range [0...1), so the result of casting any of them to int is zero. Just get rid of those casts, and you will keep your numbers in the merge result.
As an additional tip, it is much easier to debug small problems than large ones. It failed for any size greater than 2, so you should have been debugging with size 2, not 10000.
I'm learning java and I'm having an issue with my if code not running.
In the following code I'm trying to determine if a number (variable num) is a triangle number (1,3, 6, 10 etc). The code should run through and give the "Is Triangle". However it keeps spitting out Null.
I understand this is not the most effective way to do this code, but I am trying to learn how to use Classes.
public class HelloWorld {
public static void main(String[] args) {
class NumberShape {
int num = 45;
int tri = 0;
int triplus = 0;
String triresult;
public String triangle() {
while (tri < num) {
if (tri == num) {
triresult = "Is a Triangle";
System.out.println("Is a Triangle");
} else if (tri + (triplus + 1) > num){
triresult = "Is Not a Triangle";
} else {
triplus++;
tri = tri + triplus;
}
}
return triresult;
}
}
NumberShape result = new NumberShape();
System.out.println(result.triangle());
}
}
Thanks for any help provided.
Try this code :
public class HelloWorld {
public static void main(String[] args) {
class NumberShape {
int num = 10;//Try other numbers
int tri = 0;
int triplus = 0;
int res = 0;
String triresult = "Is Not a Triangle";
int[] tab= new int[num];
public String triangle() {
//to calculate the triangle numbers
for(int i = 0; i<num; i++){
res = res + i;
tab[i]=res;
}
//To check if num is a triangle or not
for(int i = 0; i<tab.length; i++){
System.out.println(">> " + i + " : " + tab[i]);
if(tab[i]== num){
triresult = num + " Is a Triangle";
break;//Quit if the condition is checked
}else{
triresult = num + " Is Not a Triangle";
}
}
return triresult;
}
}
NumberShape result = new NumberShape();
System.out.println(result.triangle());
}
}
Hope this Helps.
Step through the loop carefully. You'll probably see that there is a case where
(tri < num)
fails, and thus you fall out of the loop, while
(tri == num)
and
(tri + (triplus + 1) > num)
both fail too, so no text gets set before you fall out.
You probably want to do your if-tests within the method on just tri, not a modification of tri, so as to reduce your own confusion about how the code is working.
I'm creating a random number generator which then sorts the digits from largest to smallest. Initially it worked but then I changed a few things. As far as I'm aware I undid all the changes (ctrl + z) but now I have errors at the points where i try to call the methods. This is probably a very amateur problem but I haven't found an answer. The error i'm met with is "method in class cannot be applied to given types"
Here's my code:
public class RandomMath {
public static void main(String[] args) {
String bigger = bigger(); /*ERROR HERE*/
System.out.println(bigger);
}
//create method for generating random numbers
public static int generator(int n){
Random randomGen = new Random();
//set max int to 10000 as generator works between 0 and n-1
for(int i=0; i<1; i++){
n = randomGen.nextInt(10000);
// exclude 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 9999, 0000
if((n==1111 || n==2222 || n==3333 || n ==4444 || n==5555)
||(n==6666 || n==7777 || n==8888 || n==9999 || n==0000)){
i--;
}
}
return n;
}
//create method for denoting the bigger number
public static String bigger(int generated){
generated = generator(); /*ERROR HERE*/
System.out.println(generated);
int[] times = new int[10];
while (generated != 0) {
int val = generated % 10;
times[val]++;
generated /= 10;
}
String bigger = "";
for (int i = 9; i >= 0; i--) {
for (int j = 0; j < times[i]; j++) {
bigger += i;
}
}
return bigger;
}
}
You have not defined a method bigger(), only bigger(int generated). Therefore, you must call your bigger method with an integer parameter.
any help please, so i already wrote the prog but my if statement in my for loop is not working. the prog need to generate 6 random nos,then apply bubble sort which i already did.then the user must enter 6 numbers and these numbers must be compared against the random numbers and must say whether numbers are found in the random numbers or not. here's the code. something is wrong with the if statement ` public static void main(String[] args) {
try {
int numbers[] = new int[6]; //random numbers will be stored in new array
//2 loop will be created to avoid duplication of numbers
System.out.println("Array before Bubble sort");
for (int i = 0; i < 6; i++) {
numbers[i] = (int) (Math.random() * 40);
if (i > 0) {
for (int b = 0; b < i; b++) { //
if (numbers[b] == numbers[i]) {
i--; //decrement to continue the for loop if the integer has been repeated
}
}
}
System.out.print(numbers[i] + ","); //random numbers will be printed before using sorting bubble sort
}
//sort an array using bubble sort
bubbleSort(numbers);
System.out.println(" \nArray after bubble sort");
for (int i = 0; i < 6; i++) {
System.out.print(numbers[i] + ",");
}
BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
System.out.println("\ninput 6 number between 1 and 40");
int inputNumber = Integer.parseInt(input.readLine());
for (int b = 0; b < 6; b++) {
System.out.println("number:");
int outcome=Integer.parseInt(input.readLine());
if(outcome==numbers){
System.out.println("found in random numbers");
}else{
System.out.println("not found in random numbers");
}
}
} catch (Exception e) {
System.out.println("error");
}
}
public static void bubbleSort(int[] numbers) {
int n = numbers.length;
int temp = 0;
for (int i = 0; i < n; i++) {
for (int j = 1; j < (n - i); j++) {
if (numbers[j - 1] > numbers[j]) { //swap the element
temp = numbers[j - 1];
numbers[j - 1] = numbers[j];
numbers[j] = temp;
}
}
}
}
}`
System.out.println("\ninput 6 number between 1 and 40");
//Scanner is specifically designed for getting an input purpose and introduced in Java 5,so better use it
Scanner s = new Scanner(System.in);
//you need to have nested loop here
//But the best way to search is use binary search,as you have already sorted the array
while (s.hasNextInt()) {
//one at a time from the input is put to outcome
int outcome = s.nextInt();
boolean found = false;
for (int b = 0; b < 6; b++) {
found = false;
if (outcome == numbers[b]) {
found = true;
//remember to break the inner loop if a match is found
break;
} else {
found = false;
}
}
if (found == true) {
System.out.println("found in random numbers");
} else {
System.out.println("not found in random numbers");
}