I have a homework for college. I have to draw a rectangle with nested for loop that looks like this:
1
234
34567
4567890
567890123
for now I managed to do this:
public class DN2 {
public static void main(String[] args){
trikotnik(8);
}
static void trikotnik(int n){
for (int i = 1; i <= n; i++) {
for (int j = n; j > i; j--) {
System.out.print(" ");
}
for (int j = 1; j > 1; j--) {
System.out.print(j + " ");
}
for (int j = 1; j <= i; j++) {
System.out.print(j + " ");
}
System.out.println();
}
}
}
To draw a triangle, at most you need two nested loops, one to deal with rows and another to deal with columns.
for (int y=0; y<5; y++)
{
for (int x=0; x<9; x++)
{
//write character that should be at (x,y), i.e. (column, row)
}
}
You haven't specified anything about which numbers to should be printed where so I'm not going to guess at an algorithm but
for (int j = 1; j > 1; j--)
is saying, set j to 1 and while it is greater than one, decrement it. As you've set it to one, it can never be greater than one so this loop is skipped completely
Related
for a school project, I am trying to make an inverted half pyramid
my code is currently this
public static void main(String[] args) {
int rows = 5;
for(int i = rows; i >= 1; --i) {
for(int j = 1; j <= i; ++j) {
System.out.print(j + " ");
}
System.out.println();
}
}
with this output:
12345
1234
123
12
1
desired output:
54321
=4321
==321
===21
====1
Update (based on the updated requirement):
You need a loop to print the = equal to (rows - row number) times.
public class Main {
public static void main(String[] args) {
int rows = 5;
for (int i = rows; i >= 1; --i) {
for (int j = i; j < rows; j++) {
System.out.print("=");
}
for (int j = i; j >= 1; --j) {
System.out.print(j);
}
System.out.println();
}
}
}
Output:
54321
=4321
==321
===21
====1
Original answer:
Your inner loop should be
for (int j = i; j >= 1; --j)
i.e. for each row, it should start with the row number (i.e. i) and go down up to 1.
It is straight forward you will have to change to things: your inner loop and you will have to move println statement inside the loop
//code
public static void main(String[] args){
int rows = 5;
for (int i = rows; i >= 1; --i){
for(int j = i; j >= 1; --j)
System.out.print(j + " ");
System.out.println();
}
}
I am trying to System.out.print() a diamond out of *'s. So far I have spent a good 5 hours on trying to figure out how to reverse print the bottom triangle of the diamond.
I can worry about the spacing to complete the diamond later. (I have it worked for the most part).
If someone could explain to me what I am doing wrong and how the right way works I would greatly appreciate it.
private static void diamond()
{
int numLines = 0;
System.out.println("How many lines would you like in the Diamond?");
numLines = scan.nextInt();
if (numLines / 2 == 0) //if number is even, make odd.
{
numLines++;
}
for(int i = 0; i <= numLines ; i++) // Controls #Lines
{
if(i <= numLines / 2)
{
for(int j = 0; j < i * 2 - 1; j++) // Controls #Stars small upright triangle
{
System.out.print("*");
}
}
else
{
for(int k = numLines; k > i / 2; k--) // Controls # of spaces
{
System.out.print("*");
}
/*for(int j = numLines/2 - i, l = i; l > j; j++) // Controls #Stars small upright triangle
{
String stars = "*";
System.out.print(stars);
}*/
}
System.out.println("");
}
}
`
What happens to your attempt is that you loop through the half (of the lines) of your diamond [the number of lines in second/first half] times.
You'd want to do a if-statement each loop, not an if and a for in each loop
Probably you want this
Just adjust it for user input values
public static void main(String[] args) {
System.out.print("Reverse diamond: \n");
for (int i = 1; i < 10; i += 2) {
for (int j = 0; j < 9 - i / 2; j++)
System.out.print(" ");
for (int j = 0; j < i; j++)
System.out.print("*");
System.out.print("\n");
}
System.out.print("\n\nDiamond from starts: \n");
for (int i = 7; i > 0; i -= 2) {
for (int j = 0; j < 9 - i / 2; j++)
System.out.print(" ");
for (int j = 0; j < i; j++)
System.out.print("*");
System.out.print("\n");
}
}
output:
I am suppose to create a pyramid and multiply each number by two until it reach the middle then divide by two such as shown in example below.
However after writing my code I am unable to have the numbers double (i*2) then once it reaches the center it divides by two until the it becomes 1
My output:
package question5;
public class Pyramid {
public static void main(String[] args) {
int x = 5;
int rowCount = 1;
System.out.println("Here Is Your Pyramid");
//Implementing the logic
for (int i = x; i > 0; i--)
{
//Printing i*2 spaces at the beginning of each row
for (int j = 1; j <= i*2; j++)
{
System.out.print(" ");
}
//Printing j value where j value will be from 1 to rowCount
for (int j = 1; j <= rowCount; j++)
{
System.out.print(j+" ");
}
//Printing j value where j value will be from rowCount-1 to 1
for (int j = rowCount-1; j >= 1; j--)
{
System.out.print(j+" ");
}
System.out.println();
//Incrementing the rowCount
rowCount++;
}
}
}
this is the weird output of it
This is working... You can use math.pow method.
public class test {
public static void main(String[] args) {
int x = 5;
int rowCount = 1;
System.out.println("Here Is Your Pyramid");
//Implementing the logic
for (int i = x; i > 0; i--)
{
//Printing i*2 spaces at the beginning of each row
for (int j = 1; j <= i*2; j++)
{
System.out.print(" ");
}
//Printing j value where j value will be from 1 to rowCount
for (int j = 0; j <= rowCount-1; j++)
{
System.out.printf("%2d", (int)Math.pow(2, j));
}
//Printing j value where j value will be from rowCount-1 to 1
for (int j = rowCount-1; j >= 1; j--)
{
System.out.printf("%2d", (int)Math.pow(2, j-1));
}
System.out.println();
//Incrementing the rowCount
rowCount++;
}
}
}
Right now you're outputting j, a number from 1 to 5. You want to output 2j-1 instead, which is easy: 1 << (j - 1).
You also need to right-adjust the number. Your print statement then becomes:
System.out.printf("%4d", 1 << (j - 1));
I am trying to make my code print out the Asterisk in the image, you see below. The Asterisk are align to the right and they have blank spaces under them. I can't figure out, how to make it go to the right. Here is my code:
public class Assn4 {
public static void main(String[] args) {
for (int i = 0; i <= 3; i++) {
for (int j = 0; j <= i; j++) {
System.out.print("*");
}
for (int x = 0; x <= 1; x++) {
System.out.println(" ");
}
for (int j = 0; j <= i; j++) {
System.out.print("*");
}
}
System.out.println();
}
}
Matrix problems are really helpful to understand loops..
Understanding of your problem:
1) First, printing star at the end- That means your first loop should be in decreasing order
for(int i =7;i>=0; i+=i-2)
2) Printing star in increasing order- That means your second loop should be in increasing order
for(int j =0;j<=7; j++)
Complete code:
for(int i =7;i>=0; i=i-2){ // i=i-2 because *s are getting incremented by 2
for(int j =0;j<=7; j++){
if(j>=i){ // if j >= i then print * else space(" ")
System.out.print("*");
}
else{
System.out.print(" ");
}
}
System.out.println();// a new line just after printing *s
}
Starting loops with 1 can sometimes help you visualize better.
int stopAt = 7;
for (int i = 1; i <= stopAt ; i += 2) {
for (int j = 1; j <= stopAt; j++) {
System.out.print(j <= stopAt - i ? " " : "*");
}
System.out.println();
}
Notice, how each row prints an odd number of *s ending at the line with 7. So, you start with i at 1 and go through 3 1+2, 5 3+2, and then stopAt 7 5+2.
The nested for loop has to print 7 characters always to make sure *s appear right aligned. So, the loop runs from 1 to 7.
Here the complete code:
for(int i = 0; i < 8; i++){
if( i%2 != 0){
for(int x = 0; x < i; x++){
System.out.print("*");
}
}else{
System.out.println();
}
}
i want to print a triangle/pyramid style like:
1
323
54345
7654567
here is my code:
int lines = 5;
for (int i = 1; i < lines; i++) {
for (int j = 1; j < lines-i; j++) {
System.out.print(" ");
}
for (int j = i; j > 1; j--) { //this for loop is my problem. any solution?
System.out.print(j);
}
for (int j = i; j < i+i; j++) {
System.out.print(j);
}
System.out.println();
}
what i got is
1
223
32345
4324567
i been studying codes while working at office and i think week long i still could not find a solution to this even i use search in Google.
i am only into enhancing my logic through conditionals and no heavy object oriented or recursion yet.
The problem in your first loop is a problem you figured out in your second one! (and it has something to do with the largest number in the loop)
for (int j = i; j > 1; j--) { //this for loop is my problem. any solution?
System.out.print(j);
}
Look at the numbers on the left of the pyramid. They start where the ones on the right end (every line of the pyramid is symmetrical). And the general formula for that number is i + i - 1, where i is the line number from your outer loop.
The second row starts at 2 * i - 1 = 2 * 2 - 1 = 3. The third row starts at 2 * 3 - 1 = 5 etc.
Your second inner loop should therefore look like this:
for (int j = i + i - 1; j > i; j--) {
System.out.print(j);
}
Here is the complete fixed source.
You have to start at the i-th odd number. This is i*2-1. And you stop at i. This also fixes a spacing difference introduced by changing it to lines = 4.
int lines = 4;
for (int i = 1; i <= lines; i++) {
for (int j = 1; j < lines-i+1; j++) {
System.out.print(" ");
}
for (int j = i*2-1; j > i; j--) { //this for loop is my problem. any solution?
System.out.print(j);
}
for (int j = i; j < i+i; j++) {
System.out.print(j);
}
System.out.println();
}
Run it here: http://ideone.com/AKsc1f
int lines = 4;
for (int i = 1; i <= lines; i++) {
for (int j = 1; j < lines-i+1; j++) {
System.out.print(" ");
}
//replace this
for(int j=0; j<i-1; j++) System.out.print(i*2-j-1);
System.out.print(i);
for(int j=; j<i-1;j++) System.out.print(i+j+1);
//==========
System.out.println();
}