So i'm trying to write a programme whereby the user enters two integers .
The programm is supposed to subtract 5 from the second integer entered in a loop depending on the first number entered. (so the first number should dictate how many times it will loop.
public int getScheme1() {
while (Mark >= 20) {
System.out.printf((Mark = Mark - 5) + Mark + " ");
}
for (int Day = 1; Day <= 20; Day++) {
System.out.printf("( " + Day + "):" + Mark + " ");
}
return Mark;
}
All my code does is print the user's second input integer 20 times.
Also im sorry im totally new to java
you must call this function in your main program.
public int getScheme1 (int num1, int num2){
for(int i = 1 ; i >= num1 ; i++ ){
num2 -= 5;
}
return num2;
}
to call it simply use getScheme1(num1,num2);
Based on what you described, you are looking for something like this:
Scanner input = new Scanner(System.in); //create a scanner to get user input
int a1 = input.nextInt(); //get 2 ints from the user
int a2 = input.nextInt();
for(int i = 0; i < a1; i++) { //loop as many times as a1 specifies
a2-=5; //subtract 5 from a2 each time it loops
}
System.out.println(a2);
The key part of this is the for loop, which works in the following:
for(variable; condition; increment),
basically, what the for loop I wrote is saying:
Set i = 0 at the start. If i is meeting the condition (in this case being less then a1), then loop. The increment part is called when it finishes running the code block, it now makes i bigger (in this case 1 bigger using ++) Another important thing to note is that the first time the loop runs, i = 0.
So for example, if I wanted to loop 10 times, with a starting variable of 3 and incremented 5 each time, I'd do:
for(int i = 3; i <= 53; i+=5) {}
Also, one last thing: please look at variable naming conventions, variables shouldn't start with caps like that, they should be camelCase
Related
This is for an assignment, and is specifically requested. I know it seems somewhat pointless to create a nested for loop that only executes once, so wanted to clarify that.
The assignment question is a bit confusing to me, but states:
"Write a Java program that uses two nested FOR loops. The values used in the outer loop will be a user input value. The inner loop will use the input value divided by 2. Print a simple statement showing the values using the range of 1 to the user input number in the outer loop. The inner loop will print 1 to the divided result." However, the rubric states, "Student properly uses Java and creates a nested FOR loop and prints proper row and column number."
I initially thought I only needed to divide the input value by two and print that value, but now I feel like I'm supposed to print the input value in a simple row and column format? (If anyone else has clarity on this, please don't hesitate to drop a comment)
Basing my code on this, I'm having a really difficult time getting it to execute only once, and also having an issue printing a proper row and column. I'm attaching my attempt at the code below (this is an into-level course, fyi). Any feedback/help would be greatly appreciated!
import java.util.Scanner;
class rowCol {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter a number: ");
int n = sc.nextInt();
sc.close();
System.out.println(" \t1");
for (n = 0; n < 1; n++) {
for (n = 0; n < 1; n++) {
System.out.println("1 \t" + n);
}
System.out.println();
}
}
}
I think he meant that the outer for loop should run till n ( value entered by user ) and inner for loop will run till n/2 ( divided value )
class rowCol {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter a number: ");
int n = sc.nextInt();
sc.close();
// System.out.println(" \t1");
int val = n/2;
for (int i = 1;i<=n; i++) {
// printing from range 1 to n in the outer loop
System.out.print(i);
for (int j = 1; j<=val; j++) {
// printing from 1 to divided value in the inner loop
System.out.print(" \t" +j);
}
System.out.println();
}
}
}
When you run it , it gives output in this format .
Right now you are accepting the value from the user in the variable n and then later changing it to 0 in the loop. Doing this you are loosing the input you took from the user. You won't be able to calculate the n/2 if you loose what you accepted from the user in the first place.
You'll have to define different variables/counters for your two loops. Your outer loop will go from 1 to the number you accepted and the inner one will go from 1 to the half of the number you accepted from the user.
Your final code should look something like this (for illustration purposes only):
import java.util.Scanner;
class rowCol {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter a number: ");
int n = sc.nextInt();
sc.close();
for (int row = 1; row <= n; row++) {
// Print Row Number
System.out.print("Row: " + row + "\t");
for (int col = 1; col <= n/2; col++) {
// Print Column Number
System.out.print("Column: " + col + "\t");
}
// Print New Line
System.out.println();
}
}
}
I really don't understand how to find the sum of a sequence in Java. For instance, the program will ask for the input of the first and last number of the sequence and add the sum of the sequence(3 + 4 + 5 = 12). My System.out.println() isn't working as well. Why is this?
import java.util.Scanner;
public class SumOfASequenceTheSequel {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("First number?");
int first = Integer.valueOf(scanner.nextLine());
System.out.println("Second number?");
int second = Integer.valueOf(scanner.nextLine());
int sum = 0;
int i = first;
while (i <= second) {
sum = sum + i;
i = i++;
}
System.out.println("The sum is " + sum);
}
}
i = i++; This statement is incorrect. Because you used post incremental. In this statement first assign i's value to i after increment value. but i's value not changes. Then this while loop become infinity loop. So you need remove assignment part and only need i++;. Also you can use pre incremental (++i;). If you use pre incremental, then i = ++i; statement fine. But value assignment is not need.
If you can replace while loop using for loop, then you don't meet this problem. For loop solution below. Below Code sum += i; equals to sum = sum + i
for (int i = first; i <= second; i++) {
sum += i;
}
i++; is called Post Increment equal to i = i + 1; So you just need i++;, not i = i++;.
As others have pointed out, because you are doing post-increment and assignment in the same statement, (i = i++;), your program is running in an infinite loop.
You might want to change it to either a pre-increment assignment (i = ++i;) or even better a plain pre or post increment (i++;).
Look at this link to understand the difference between pre and post increment operators.
I will recommend a for loop instead of while loop for better readability. See the following snippet:
for(int i = first; i <= second; i++) {
sum = sum + i;
}
If you like Stream API instead of traditional loops, you can also print the sum the following way:
System.out.println("The sum is " + IntStream.rangeClosed(first, second).sum());
On a side note, you might want to close the Scanner resource after you are done using it to avoid resource leak, like so: scanner.close();
I'm new to java and I have an assignment asking to prompt user for a number between 2 and 10 and it is supposed to print out multiples of that number. It is also supposed to use a for loop.
I think I have the general idea with the for loop I'm just trying to figure out how to do the multiples. Any help is greatly appreciated! This is where I am so far:
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.println("Please Enter a number between 2 and 10:");
for(int i = 2; i<= 100; i++){
System.out.println(+ i);
}
I suggest thinking about how you would go about doing the task mentally. When you're counting integers, you will add one each time (i++). When you're counting by, say threes, you will add three each time. You need to store your scanner's read value to a variable (don't try to read the scanner each time!) and adjust i++ in your loop to add the number you read from the scanner instead.
Begin with:
int step = in.nextInt();
if(step >= 2 && step <=10){
for(int i = 0; i <=100; ???){
System.out.println(+ i);
}
} else {
System.out.println("The step value was not between 2 and 10.");
}
I will leave you at this point as learning it for yourself is far more valuable than any Stack Overflow answer could ever be. If you are still stumped, I can guide you farther in the right direction.
You should ensure that the user can only enter numbers between 2 and 10, and you will need to store the input for use in your for loop. For example:
int num = 0;
Scanner in = new Scanner(System.in);
do
{
System.out.print("Please enter a number between 2 and 10:")
num = in.nextInt();
System.out.println();
} while((num < 2) || (num > 10));
Followed by your for loop.
A multiple of a number is that number times something.
So one multiple of i would be i * 13 (for example).
of course you need to get number from the Scanner "in" object
for (int i=2; i < 13; i++) {
System.out.println(" Multiple (" + i + ") = " + i*number;
}
import java.util.*;
public class ulang {
public static void main(final String[] args) {
int a;
int b;
int sum;
Scanner scan = new Scanner(System.in);
System.out.println("Enter num 1: ");
a = in.nextLine();
System.out.println("Enter num 2: ");
b = in.nextLine();
{
sum = a + b;
}
for (i = 0; i < 5; i++) {
(sum >= 10)
System.out.println("Congratulations");
else
System.out.println("Sum of the number is Less than 10");
}
}
}
I'm weak on looping especially in Java. So I need some corrections on my coding, but I have no idea how to fix it.
The coding should run like this: User need to insert 2 numbers and the program will calculate the sum of both number. After that, the program will determine if the total of sum is >=10 or <10. If the sum >=10, "Congratulations" will appear but if it is <10, then "The sum of number less than 10" will appear. How to fix it?
This is the immediate problem:
(sum>=10)
I believe you meant that to be an if statement:
if (sum>=10)
Additionally:
You're trying to use an in variable, but the Scanner variable is called scan
Scanner.nextLine() returns a String - I suspect you wanted Scanner.nextInt()
Your for loop uses a variable that hasn't been declared. You probably meant:
for (int i = 0; i < 5; i++)
A few other suggestions though:
The sum isn't going to change between the loop iterations... why are you looping at all?
You've got a new block in which you're calculating the sum, but for no obvious reason. Why?
It's generally a good idea to declare variables at the point of initialization, e.g.
Scanner scan = new Scanner(System.in);
System.out.println("Enter num 1: ");
int a = scan.nextInt();
System.out.println("Enter num 2: ");
int b = scan.nextInt();
int sum = a + b;
Given that you want to take the same basic action (writing a message to the screen) whether or not the user was successful, you might consider using the conditional operator like this:
String message = sum >= 10 ? "Congratulations"
: "Sum of the number is Less than 10";
System.out.println(message);
That would then allow you to refactor the loop to only evaluate the condition once:
String message = sum >= 10 ? "Congratulations"
: "Sum of the number is Less than 10";
for (int i = 0; i < 5; i++)
{
System.out.println(message);
}
(sum>=10)
This line needs an if at the beginning, or it won't be read as a branch.
if (sum >= 10)
You also should name your main-class Ulang, because java class identifiers should start with an upper case letter, for readability.
The loop should look like the following:
for (int i = 0; i < 5; i++) {
The first part defines the counter and assigns zero to it. The second is your condition and the last counts for you.
for (int i = 0; i < 5; i++) {
if (sum >= 10)
System.out.println("Congratulations");
else
System.out.println("Sum of the number is Less than 10");
}
I have to write a java program where the solution will include the printing of the arrow tip figure depending on the number of rows. Below are example of how the result should look. However, I cannot do this until I understand for loops. I know I have to work with the rows and columns and possibly nested loops. I just dont know how to connect the row with the columns using for loops. Please help me in understanding these loops. Thanks!
Example #1 (odd number of rows)
>
>>>
>>>>>
>>>>>>>
>>>>>
>>>
>
Example #2 (even number of rows)
>
>>>
>>>>>
>>>>>>>
>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>
>>>>>>>
>>>>>
>>>
>
a for loop will loop through a collection of data, such as an array. The classic for loop looks like this:
for(counter=0;counter <= iterations;counter++){ }
the first param is a counter variable. the second param expresses how long the loop should last, and the 3rd param expresses how much the counter should be incremented by after each pass.
if we want to loop from 1 - 10, we do the following:
for(counter=1;counter<=10;counter++){ System.out.println(counter); }
if we want to loop from 10 - 1, we do the following:
for(counter=10;counter>=1;counter--){ System.out.println(counter); }
if we want to loop through a 2 dimensional collection, like...
1 2 3
4 5 6
7 8 9
int[][] grid = new int[][] {{1,2,3},{4,5,6},{7,8,9}};
we need 2 loops. The outer loop will run through all the rows, and the inner loop will run through all the columns.
you are going to need 2 loops, one to iterate through the rows, one to iterate through the columns.
for(i=0;i<grid.length;i++){
//this will loop through all rows...
for(j=0;j<grid[i].length;j++){
//will go through all the columns in the first row, then all the cols in the 2nd row,etc
System.out.println('row ' + i + '-' + 'column' + j + ':' + grid[i][j]);
}
}
In the outer loop, we set a counter to 0 for the first parameter. for the second, to calculate how many times we will loop, we use the length of the array, which will be 3, and for the third param, we increment by one. we can use the counter, i, to reference where we are inside the loop.
We then determine the length of the specific row by using grid[i].length. This will calculate the length of each row as they are being looped through.
Please feel free to ask any questions you may have regarding for loops!
EDIT: understanding the question.....
You are going to have to do several things with your code. Here we will store the number of lines in a variable, speak up if you need to pass in this value to a method.
int lines = 10; //the number of lines
String carat = ">";
for(i=1;i<=lines;i++){
System.out.println(carat + "\n"); // last part for a newline
carat = carat + ">>";
}
The above will print out carats going all the way up. We print out the carat variable then we make the carat variable 2 carats longer.
.... the next thing to do is to implement something that will decide when to decrease the carats, or we can go up half of them and down the other half.
Edit 3:
Class Test {
public static void main(String[] args) {
int lines = 7;
int half = lines/2;
boolean even = false;
String carat = ">";
int i;
if(lines%2==0){even = true;} //if it is an even number, remainder will be 0
for(i=1;i<=lines;i++){
System.out.println(carat + "\n");
if(i==half && even){System.out.println(carat+"\n");} // print the line again if this is the middle number and the number of lines is even
if(((i>=half && even) || (i>=half+1)) && i!=lines){ // in english : if the number is even and equal to or over halfway, or if it is one more than halfway (for odd lined output), and this is not the last time through the loop, then lop 2 characters off the end of the string
carat = carat.substring(0,carat.length()-2);
}else{
carat = carat + ">>"; //otherwise, going up
}
}
}
}
Explanation and commentary along shortly. Apologies if this is over complicated (i'm pretty sure this is not even close to the best way to solve this problem).
Thinking about the problem, we have a hump that appears halfway for even numbers, and halfway rounded up for the odd numbers.
At the hump, if it is even, we have to repeat the string.
We have to then start taking off "<<" each time, since we are going down.
Please ask if you have questions.
I had the same question for a homework assignment and eventually came to a correct answer using a lot of nested if loops through a single for loop.
There is a lot of commenting throughout the code that you can follow along to explain the logic.
class ArrowTip {
public void printFigure(int n) { //The user will be asked to pass an integer that will determine the length of the ArrowTip
int half = n/2; //This integer will determine when the loop will "decrement" or "increment" the carats to String str to create the ArrowTip
String str = ">"; //The String to be printed that will ultimately create the ArrowTip
int endInd; //This integer will be used to create the new String str by creating an Ending Index(endInd) that will be subtracted by 2, deleting the 2 carats we will being adding in the top half of the ArrowTip
for(int i = 1; i <= n; i++) { //Print this length (rows)
System.out.print(str + "\n"); //The first carat to be printed, then any following carats.
if (n%2==0) { //If n is even, then these loops will continue to loop as long as i is less than n.
if(i <= half) { //This is for the top half of the ArrowTip. It will continue to add carats to the first carat
str = str + ">>"; //It will continue to add two carats to the string until i is greater than n.
}
endInd = str.length()-2; //To keep track of the End Index to create the substring that we want to create. Ultimately will determine how long the bottom of the ArrowTip to decrement and whether the next if statement will be called.
if((endInd >= 0) && (i >= half)){ //Now, decrement the str while j is greater than half
str = str.substring(0, endInd); //A new string will be created once i is greater than half. this method creates the bottom half of the ArrowTip
}
}
else { //If integer n is odd, this else statement will be called.
if(i < half+1) { //Since half is a double and the integer type takes the assumption of the one value, ignoring the decimal values, we need to make sure that the ArrowTip will stick to the figure we want by adding one. 3.5 -> 3 and we want 4 -> 3+1 = 4
str = str + ">>"; //So long as we are still in the top half of the ArrowTip, we will continue to add two carats to the String str that will later be printed.
}
endInd = str.length()-2; //Serves the same purpose as the above if-loop when n is even.
if((endInd >= 0) && (i > half)) { //This will create the bottom half of the ArrowTip by decrementing the carats.
str = str.substring(0, endInd); //This will be the new string that will be printed for the bottom half of the ArrowTip, which is being decremented by two carats each time.
}
}
}
}
}
Again, this was for a homework assignment. Happy coding.
Here is a simple answer for you hope it helps! Cheers Logan.
public class Loop {
public static void main(String[] args) {
for (int i = 0; i < 10; i++) {
int count = i;
int j = 0;
while (j != count) {
System.out.print(">");
j++;
}
System.out.println();
}
for (int i = 10; i > 0; i--) {
int count = i;
int j = 0;
while (j != count) {
System.out.print(">");
j++;
}
System.out.println();
}
}
}
For making a 'for' loop:
public class Int {
public static void main(String[] args) {
for (Long num = 1000000L; num >= 9; num++) {
System.out.print("Number: " + num + " ");
}
}
}
Output:
Number: 1008304 Number: 1008305 Number: 1008306 Number: 1008307 ...