Develop Reference

For loop for increasing pyramid pattern

I am trying to figure out how to increment a pyramid based on input from the user.\
If a user enters the number 3, my program will print a pyramid of height 3, three times.\
What I would like it to do instead, is to print 3 pyramids, but the first pyramid should have a height of 1, and the second a height of 2, and the third a height of 3.
Here is my code:
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt();
for (int l = 0; l < n; l++) {
System.out.println("Pyramid " + n);
for (int i = 1; i <= n; i++) {
for (int j = 0; j < n - i; j++) {
System.out.print(".");
}
for (int j = 0; j < i; j++) {
System.out.print("#");
}
for (int j = 1; j < i; j++) {
System.out.print("#");
}
for (int k = 0; k < n - i; k++) {
System.out.print(".");
}
System.out.println();
}
}

You use l to keep track of the number of pyramid you're working on, so you could just use it in the loop instead of n. Note that l starts with 0, not 1, so you may want to amend the loop accordingly and run from 1 to n, not from 0 to n-1
for (int l = 1; l <= n; l++) { // Note the loop starts at 1
System.out.println("Pyramid " + l);
for (int i = 1; i <= l; i++) { // Note the usage of l instead on n
for (int j = 0; j < l - i; j++) {
System.out.print(".");
}
for (int j = 0; j < i; j++) {
System.out.print("#");
}
for (int j = 1; j < i; j++) {
System.out.print("#");
}
for (int k = 0; k < l - i; k++) { // Note the usage of l instead on n
System.out.print(".");
}
System.out.println();
}
}

All you have to change is this part of code
System.out.println("Pyramid " + (l+1));
for (int i = 1; i <= l+1; i++) {

How to make diamond pattern using java?

How to make this pattern
if input N = 5
Output :
Mine is like this, it become 2N
if input N = 5
Output
Here's my code
int i,j;
for(i = 0; i <= n; i++)
{
for(j = 1; j <= n - i; j++)
System.out.print(" ");
for(j = 1; j <= 2 * i - 1; j++)
System.out.print("*");
System.out.print("\n");
}
for(i = n - 1; i >= 1; i--)
{
for(j = 1; j <= n - i; j++)
System.out.print(" ");
for(j = 1; j <= 2 * i - 1; j++)
System.out.print("*");
System.out.print("\n");
}
What should i fix??

You can check odd numbers in your loop. Please see the following example:
public static void main(String[] args) {
printPattern(5);
}
private static void printPattern(int n) {
int i, j;
for (i = 0; i <= n; i++) {
if (i % 2 != 0) {
for (j = 1; j <= (n - i)/2; j++) {
System.out.print(" ");
}
for (j = 0; j < i; j++) {
System.out.print("*");
}
System.out.println();
}
}
for (i = n - 1; i >= 1; i--) {
if (i % 2 != 0) {
for (j = 1; j <= (n - i)/2; j++) {
System.out.print(" ");
}
for (j = 0; j <i; j++) {
System.out.print("*");
}
System.out.println();
}
}
}

Instead of running these two loops from 0 to N twice. Just run half N/2 in each loop.
Example:
public static void main(String[] args) {
int n = 10;
for (int i = 0; i <= (n / 2 + 1); i++) {
for (int j = 1; j <= n - i; j++) System.out.print(" ");
for (int j = 1; j <= 2 * i - 1; j++) System.out.print("*");
System.out.print("\n");
}
// N/2
for (int i = n / 2 - 1; i >= 1; i--) {
for (int j = 1; j <= n - i; j++) System.out.print(" ");
for (int j = 1; j <= 2 * i - 1; j++) System.out.print("*");
System.out.print("\n");
}
}

String,which repeats ,but not starts from the beginning in Java (diamond pattern

This is the work that i done so far:I have to print diamond pattern which always starts with uppercase from string, which repeats,but not always starts from the beginning.
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
String userInput = keyboard.next();
userInput = Character.toUpperCase(userInput.charAt(0)) + userInput.substring(1);
int i;
int j;
if (userInput.length() % 2 != 0) {
for(i = 1; i < userInput.length(); i += 2) {
for(j = 0; j < userInput.length() - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
System.out.print(userInput.charAt(j));
}
System.out.println("");
}
for(i = userInput.length(); i > 0; i -= 2) {
for(j = 0; j < userInput.length() - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
System.out.print(userInput.charAt(j));
}
System.out.print("\n");
}
} else {
for(i = 2; i < userInput.length(); i += 2) {
for(j = 0; j < userInput.length() - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
System.out.print(userInput.charAt(j));
}
System.out.println("");
}
for(i = userInput.length(); i > 0; i -= 2) {
for(j = 0; j < userInput.length() - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
System.out.print(userInput.charAt(j));
}
System.out.print("\n");
}
}
}
For example my input is "Peter".
So my output is:
P
Pet
Peter
Pet
P
but it must be:
P
Ete
Rpete
Rpe
T
I dont know what to change to make this work

Here's a shorter version of your code:
public static void main(String[] args) {
String userInput = "Peter";
int length = userInput.length();
int m, j, i, n = 0;
for (m = length % 2 > 0 ? 1 : 2; m < length * 2; m += 2) {
i = m < length ? m : length * 2 - m;
for (j = 0; j < length - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
char c = userInput.charAt(n++ % length);
c = j == 0 ? Character.toUpperCase(c) : Character.toLowerCase(c);
System.out.print(c);
}
System.out.println("");
}
}

You need some few changes:
Declare int n=0; after int j;
Always print userInput.charAt(n++ % userInput.length()) instead of charAt(j)
In order to get only the first character in line in uppercase:
char c = userInput.charAt(n++ % userInput.length());
c = j == 0 ? Character.toUpperCase(c) : Character.toLowerCase(c);
System.out.print(c);
Check the modulo operator.
With these changes, you'll get this output:
P
Ete
Rpete
Rpe
T

Given the fact that the input itself gets printed in a cylic manner, we can make use out of it. My proposal would be to concatenate the input string and print out the substrings which are determined by the structure of the diamond pattern.
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
String userInput = keyboard.next();
String concatenated = userInput;
// build up the index array
int i, cumSum = 0;
ArrayList<Integer> helperIndex = new ArrayList<>();
for(i = 1; i < userInput.length(); i += 2) {
helperIndex.add(i);
cumSum += i;
}
for(i = userInput.length(); i > 0; i -= 2) {
helperIndex.add(i);
cumSum += i;
}
int numOfWordRepitition = cumSum / userInput.length() ;
for (i = 0; i < numOfWordRepitition; i++){
concatenated += userInput;
}
// print out diamond
String substr;
int prev = helperIndex.get(0);
int next = helperIndex.get(0);
substr = concatenated.substring(0 , helperIndex.get(0));
System.out.println(Character.toUpperCase(substr.charAt(0)) + substr.substring(1));
for(i = 1; i < userInput.length(); i++){
next += helperIndex.get(i);
substr = concatenated.substring(prev , next);
substr = Character.toUpperCase(substr.charAt(0)) + substr.substring(1);
System.out.println(substr);
prev = next;
}
}

How to create a square with numbers?

I'm trying to create a square shape with numbers like this:
1234
2341
3412
4123
How would I go about doing that?
for (int i = 1; i <= 4; i++) {
for (int j = i; j <=4; j++) {
System.out.print(j);
}
System.out.println();
}
This prints:
1234
234
34
4
How do I get it to restart at 1 again?

You can do by using modulo
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
System.out.print((j + i) % 4 + 1);
}
System.out.println();
}
output
1234
2341
3412
4123

You need to update to
for (int i = 1; i <= 4; i++) {
for (int j = i; j <=4; j++) {
System.out.print(j);
}
for (int j = 1; j < i; j++) {
System.out.print(j);
}
System.out.println();
}

add one more for loop
for (int i = 1; i <= 4; i++) {
for (int j = i; j <=4; j++) {
System.out.print(j);
}
for (int j = 1; j <i; j++) {
System.out.print(j);
}
System.out.println();
}

There's probably a simpler way, but this should work:
for (int i = 1; i <= 4; i++) {
for (int j = 3; j <= 6; j++) {
System.out.print ((i + j) % 4 + 1);
}
System.out.println();
}

try this:
public class MyClass {
public static void main(String args[]) {
int count = 0;
for (int i = 1; i <= 4; i++) {
for (int j = i; j <=4; j++) {
System.out.print(j);
count += 1;
}
if(count < 4){
int remain = 4 - count; // to identify how many times it goes again
for(int k=0;k<remain;k++){
System.out.print(k+1);
}
}
count = 0;
System.out.println();
}
}
}
Output:
1234
2341
3412
4123

How about this?
for(int i = 1; i <= 4; i++){
for(int j = 1; j <= 4; j++){
System.out.print(((i + j + 2) % 4) + 1);
}
System.out.println();
}
If you look at the expected output, it has a pattern, which is restricted to a finite and known sequence of numbers. Modulus is the ideal option to handle cases like this.

for (int i = 1; i <= 4; i++) {
for (int j = 0; j <= 3; j++) {
System.out.print(((i + j) % 4) + 1);
}
System.out.println();
}
Modulus (%) gives the remainder of one number divided by another, so (i+j) % 4 always gives a result between 0 and 3.
Add one to that to get the value you want (between 1 and 4).

Finding the largest row and column, solution is inconsistent

Where is the logic error?.. Sometimes the solution is correct and sometimes it is not. The program is suppose to calculate the row with the greatest sum and column with the greatest sum. For example:
1 1 1 1
0 0 1 0
0 0 1 0
0 0 1 0
Then the output would be:
largest row = 0
largest column = 2 //since count starts at 0
This is what I have:
import java.util.Random;
public class LargestRowAndColumn {
public static void main(String[] args) {
Random f = new Random();
int[][] m = new int[4][4];
for (int i = 0; i < m.length; i++) {
for (int j = 0;j < m[0].length; j++) {
m[i][j] = f.nextInt(2);
}
}
for (int i = 0; i < m.length; i++) {
for (int j = 0;j < m[0].length; j++) {
System.out.print(m[i][j] + " ");
}
System.out.println();
}
System.out.println("The largest row is index: " + computeRow(m));
System.out.println("The largest column is index: " + computeColumn(m));
}
public static int computeRow(int[][] m) {
int[] count = new int[m.length];
int sum;
for (int i = 0; i < 4; i++) {
sum = 0;
for (int j = 0; j < 4; j++) {
sum = sum + m[i][j];
}
count[i] = sum;
}
int maxIndex = 0;
for (int i = 0; i < i + 1; i++) {
for (int j = count.length - 1; j >= i; j--) {
if (count[i] < count[j]) {
maxIndex = j;
break;
}
}
}
return maxIndex;
}
public static int computeColumn(int[][] m) {
int[] count = new int[m.length];
int sum = 0;
for (int i = 0; i < 4; i++) {
sum = 0;
for (int j = 0; j < 4; j++) {
sum = sum + m[j][i];
}
count[i] = sum;
}
int maxIndex = 0;
for (int i = 0; i < i + 1; i++) {
for (int j = count.length - 1; j >= i; j--) {
if (count[i] < count[j]) {
maxIndex = j;
break;
}
}
}
return maxIndex;
}
}

Your maxIndex nested loop is too complex. It should be a single loop, checking the current max value seen so far with the current item in the loop. Something like this:
int maxIndex = 0;
for (int i = 1; i < count.length; i++) {
if (count[i] > count[maxIndex]) {
maxIndex = i;
}
}
return maxIndex;

Your code is correct , but
for (int i = 0; i < m.length; i++) {
for (int j = 0;j < m[0].length; j++) {
m[i][j] = f.nextInt(2);
}
}
for (int i = 0; i < m.length; i++) {
for (int j = 0;j < m[0].length; j++) {
System.out.print(m[i][j] + " ");
}
Because of the two loops:
You are creating two random 2-dimensional array instead of one.
There is one which is being printed and the other one which is not being printed but being used for index values you require so do :
System.out.print("Index" + "\t0"+"\t1"+"\t2"+"\t3" +"\n");
System.out.print("--------------------------------------------\n");
for (int i = 0; i < m.length; i++) {
System.out.print(i+ "|\t");
for (int j = 0;j < m[0].length; j++) {
m[i][j] = f.nextInt(101);
System.out.print(m[i][j] + " \t");
}
System.out.println();
}
This will also print the index, which may assist you

Why you made your job difficult. Make 2 loops, 1 for calculating the row with biggest sum, 1 for calculating the line with the bigger sum.
You don't need an int array count[i]. In your example you calculate the row with the greatest sum, you don't need to know the sum of every row after the for loop finished, so you can use a simple int bigRow.
int bigRow = 1, sumRow = 0;
// We assume that 1st row is the biggest
// Calculate the sumRow
for (int j=0;j<n;j++)
sumRow = sumRow + m[i][j] ;
// At this moment our maximum is row 1 with its sum.
// Now we compare it with the rest of the rows
// If another row is bigger, we set him as the biggest row
for ( int i=1;i<n;i++) // We start with row 2 as we calculated the 1st row
{ int auxRow = 0;
for (int j=0;j<m;j++)
{ auxRow = auxRow + m[i][j] ; }
if (auxRow > sumRow ) { auxRow=sumRow ; bigRow = i;}
}
Do the same with lines.
int bigLine = 1, sumLine = 0 ;
Let me know if you have another problem.