Calculate Sum Of All Integers Between 1 And Given Integer N
Aug 3, 2014
So I wrote a method that simply calculates the sum of all integers between 1 and a given integer n. The method works fine however, as n gets big the solution will have time and space problems. Some I'm just curious if there is a better method than my iterative one that would produce a better Big O value.
public static int sum(int n)
{
int total = 0;
for (int i = 1; i <=n; i++)
total += i;
return total;
}
So this I need to write a program which asks the user to enter any string, but the string has to have integers inside. I need to calculate the sum of those integers mentioned in the String. Also return 0 if there aren't any.
User input: I have a 91 Output: 10
I cant seem to find a way scan through the string to find the integers and add them.
String x1=input.next(); char digit= x1.charAt(3);} public static int findDigitSum (String x)?
-Create a main method declares and creates an integer array called nums that can hold 15 integers.
-Use a for loop to fill that array with multiples of 3: 0, 3, 6, 9, etc.
-Then use similar for loop to print each value in the array on one line, with each value separated by a single space.
-Compile and run the program to see the result:0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
As you write other methods, you'll also modify the main method to make calls to them. The printArray MethodWrite a method called printArray that accepts an integer array as a parameter. This method does not return a value, and must be declared as static so that the main method can call it. Instead of printing the array in the main method, move that loop into this method. Call the printArray method from the main method. Compile and run the program to verify it prints the sam result as before.Add a println statement so that after printing the array values on one line, it then moves to the following line.Finally, modify the loop in the printArray method so that, instead of using a traditional for loop, it instead uses a for-each loop. Compile and run the program again.
Part III: More Array Methods
The linearSearch Method In lecture we looked at a method that performed a binary search on a sorted array. A much simpler (though much less efficient) search is a linear search, that simply starts at the front of the array and looks at each element in turn until it finds it or reaches the end.Create a method called linearSearch that accepts an integer array and a single int value as parameters. The goal of the method is to find the second parameter (the target) in the array. The method should return a single int representing the index of the target value. This method should not print any output itself. In this method, use a traditional for loop to scan through the elements in the array. As soon as you find the target value, return the index of that value.
If you scan through the entire array without finding the target value, return a -1.Modify the main method to call the linearSearch method and print the results. Call it twice, searching for the value 18 (which it should find) and the value 10 (which it should not). Including the previous activity, the output of the main method should now look similar to this:0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
The index of 18 is 6
The index of 10 is -1
The sumArray Method
The sumArray method should take an integer array as a parameter and return a single integer representing the sum of all values in that array.Use a for-each loop to access each value in the array and compute a running sum. After the loop, return the total.Call the method from the main method, producing the following augmented output:0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
The index of 18 is 6
The index of 10 is -1
The sum of this array is 315
The addValue Method...The addValue method should accept an integer array and a single int as parameters. The purpose of the method is to add the second parameter to EACH value in the array. The addValue method does not return a value, but the elements inside the array will be modified. Call the addValue method from the main method, adding 100 to each element in the array. Then call the printArray method again to see the modified array values:0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
The index of 18 is 6
The index of 10 is -1
The sum of this array is 315 100 103 106 109 112 115 118 121 124 127 130 133 136 139 142
Test a Different Array..Finally, duplicate the content of the main method to perform similar tests on another array. Instead of filling it with multiples of 3, fill it with multiples of 4. And instead of using an array size of 15, use an array size of 20.Modify the values search for to include one that is in the array and one that isn't.Rerun the main method and carefully check the results.If you haven't been doing it all along (which you should), make sure the appropriate class and method documentation is included.When you're satisfied that all methods are working correctly, modify the main method to delete the second array tests.
How do I code this without having the need to use iterator? Code a Java method that accepts an ArrayList of integers and an integer. The method should delete all elements in the array list exactly divisible by the integer and return the number of remaining elements.
Write a function that accepts an array of non-negative integers and returns the second largest integer in the array.
Return -1 if there is no second largest.
The signature of the function is int f(int[ ] a)
Examples:
if the input array isreturn{1, 2, 3, 4}3{{4, 1, 2, 3}}3{1, 1, 2, 2}1{1, 1}-1{1}-1{}-1
In the signature what I understood is, I should write my function with the given signature,
The return type is "int"
method name is "f"
parameter is "a" right ?
Writing my doubts beside the particular line in the code
public static void main() // In the answer why they didn't use the class ?
In main method why they didn't use parameters ?(String[] args)
{ a1(new int[]{1, 2, 3, 4}); // what is "a1" here is it array name ? this line initializing the array ? a1(new int[]{4, 1, 2, 3}); a1(new int[]{1, 1, 2, 2}); a1(new int[]{1, 1}); a1(new int[]{1}); a1(new int[]{}); }
static int a1(int[] a) // what is "a" here parameter ? and "a1" is method name ? why they used the array name and method name same ?
{ int max1 = -1; int max2 = -1; for (int i=0; i<a.length; i++)
I have a problem where I have to create random integers from 1 to n + 1. When the array is displayed I have to find the missing integer from the values that are displayed and show that value. I have to use O(n^2) and O(n) operations. I have created this code so far but I cannot figure out how to make my values display n + 1. It is only displaying values 1, 2, 3, 4 and 5 in random order. I also cannot figure out how to find the missing value. I have created a boolean displayed statement but can't determine how to use it in this code.
=Java import java.util.Random; public class Task6 { public static void main(String[] args) { int[] numbers = new int[7]; //create array of numbers Random random = new Random(); boolean displayed = false; //boolean value to determine if number was displayed
Write a method maxOccurrences that accepts a list of integers as a parameter and returns the number of times the most frequently occurring integer (the “mode”) occurs in the list. Solve this problem using a map as auxiliary storage.
lines 7, 8, &12 "primes" are underline in red (prime cannot be resolved) is what pops up when i hover over the x's.
i don't get why that is.
package assignment7; public class Exercise3 { public static void main(String[] args) { Prime.setSize(1000); for (int p = Primes.next(); p < 30; p = Primes.next())
Lines 7, 8, &12 "primes" are underline in red (prime cannot be resolved) is what pops up when i hover over the x's.
I don't get why that is.
Java Code :
public class Exercise3 { public static void main(String[] args) { Prime.setSize(1000); for (int p = Primes.next(); p < 30; p = Primes.next()) { int n = (int)Math.round(Math.pow(2,p)) - 1; System.out.printf("%d 2^%d-1%d", p, p, n); if (Primes.isPrime(n))
public class MyInteger { private int value; public MyInteger(int number){ value = number; System.out.println("Constructor created with value of " + value);
[code]....
I can't seem to get the value for integer1 and integer2 to pass with the setValue method. I get a runtime error stating the I need to have an int value for these two integers.
After the code is executed the array is supposed to contain 2,3,5,3,2. However, prime[4-0]= prime[i] and prime[4-1]= prime[i]... doesn't the loop terminate before it iterates a third time? Why are there five integers instead of only two?
import java.util.Arrays; import javax.swing.JOptionPane; public class Student { public static void main(String args[]) { String [] A =new String [4]; //krijon tabelen e emrave
[Code] ....
It Prints [firstname,secondname,thirdname,fourthname]
and [0,0,7,9]
The problem is that the first 2 integers of the second array are always 0 even if i put another grade like for example 6 or 7...
Our teacher asked to input the names and grades of the students using JOptionPane and then find the MINIMUM grade and how many times this grade is repeated...
Create a loop where you add the integers from 1 to 50.
public class Sum50 { public static void main(String[] args) { int sum = 0; int max = 50; for(int i = 0;i <= max; i++){ sum=sum+i; } System.out.println("Sum is " + sum); } }
I need to write a class in that uses the For loop and does the following things: asks user to input two integers, the second larger than the first. Next, use a for loop to sum the numbers between the two integers, including the original integer. For example: 5&8 would be 5+6+7+8 and lastly prints out the sum of this.
I have successfully been able to do the first part but when it comes to the For Loop I am a bit lost here is what I have so far
import java.util.Scanner; public class Question3 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Please enter an integer"); int num1 =sc.nextInt(); System.out.println("please enter a larger integer"); int num2=sc.nextInt(); int sum=0; for(int i=num1; i<=num2;i++); } }
I have this code running correctly in Eclipse all except that it seems no matter where I declare, highest, lowest, average they always seem to stay at "0". I have a feeling the location of the Initialization is not the error since I have tried moving it to inside differ loops.
Stipulations on writing this code are:
Note: You do not need to use array to save each input score for this lab. A Single loop to read in each grade, compare with the current highest grade, lowest grade, and calculate the running sum at the same time.
import java.util.Scanner;
/*Write a program that prompts the user to enter the total number of students first. *Then ask the user to input each student’s grade and use loop statements to read in each grade. *Check input grade to make sure 0<=grade<=100, if the user input any other number, print out warning message and ask the user to input a new grade. Display the highest score, the lowest score and the average. */
public class LoopStatements { // Main Method public static void main(String[] args) { // Initialize int grade = 0; // grade value
my code is below and i want to read only integers.BUT the text file is starting with text and it stops executing without reading the numbers.Also i want to add the 3 parameters of each line.
try{ File fl = new File("C:/Users/Mario/Desktop/testing.txt"); //BufferedReader rd = new BufferedReader(new FileReader(fl)); Scanner sc = new Scanner(fl).useDelimiter("s+"); LinkedList<Integer> temps = new LinkedList<>(); sc.useDelimiter(System.getProperty("line.separator")); while(sc.hasNext()){
CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(port); if (portIdentifier.isCurrentlyOwned()) { System.out.println("Error: Port is currently in use"); } else { CommPort commPort = portIdentifier.open(this.getClass().getName(), 2000);
[Code].....
To set the serial port parameters i need to use Integers instead of strings.
I am trying to write a method that returns the busiest hour in a logAnalyzer class that read web server data and analyze hourly access patterns and stores them in an array. My problem is, in order to get the busiest hour, I need to go through the hourCounts array to find the element with the biggest count.
Develop a method that accepts as data input three integer numbers, calculates the sum and the product of the numbers, and displays the sum and product.
1. Prompt the user to input two positive integers: firstNum and secondNum (firstNum must be smaller than secondNum). 2. Output all the even numbers between firstNum and secondNum inclusive. 3. Output the sum of all the even numbers between firstNum and secondNum inclusive. 4. Output all the odd numbers between firstNum and secondNum inclusive. 5. Output the sum of all the odd numbers between firstNum and secondNum inclusive.
*Use while loop int firstNum, secondNum; Scanner keyboard = new Scanner(System.in); System.out.println("Enter an integer: "); firstNum = keyboard.nextInt();
[Code] ....
What to do with the while loop and how to find even and odd numbers.
I have a method that receives an array of integers and saves the ID of the user inside the array of integers and I keep getting the error: "int[] cannot be converted to int".Here is the code:
public boolean Borrow (String TitleOrAuthor,int id){ int count = 0; int b1 = 0; int BookCount [] = new int [b1]; for (int i=0;i<Bcount;i++){ if(Booklist[i].getTitle().equals(TitleOrAuthor)) for(int j=0;j<b1;j++){ BookCount [j]= Booklist[i].getCopies(); BookCount [j]= id; b1++;
import java.text.DecimalFormat; public class Money { //Fields for money will hold dollars and cents private long dollars; private long cents;
My task is to use those fields and make a toString method that returns them like a dollars sign. For instance, if there are 32 dollars and 40 cents, then in my String method I have to return something similar to this "$32.40."
I have already tried some of the methods, but they don't seem to work fine.
I have a code like following. x and y are both Integers and have same values (e.g. 5). But they are interpreted as different values. Then, it validates the following condition.
Java Code: if (x != y) { "x and y are different..." } mh_sh_highlight_all('java');
I am workinh with a couple of functions that deal with two dimensional (square) arrays of integers, doing things like checking equality, etc. For example, I know that I get an ArrayOutOfBoundsException in the isEqual function, but I don't know why.
public class MatrixUtils { //This function checks if two matrices are equal public static boolean isEqual(int A[][], int B[][]) { for(int i=0; i<A.length; i++) { for(int j=0; j<A.length; i++) { if (A[i][j] != B[i][j]) return false;
