JavaScript pyramid - javascript

I'm trying to print a pyramid that has odd numbers for edges. For example output should be:
.......5
...3,4,3
1,2,3,2,1
(dots are here just to show formating)
I managed to write:
function p(n){
let string = "";
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= n - i; j++) {
string += " " ;
}
for (let k = 1; k <= 2*i-1; k++) {
string += n-k +1;
}
string += "\n";
}
console.log(string);
}
p(5);
But I'm not sure how to continue to get wanted result

You can try it :
function p(n){
let string = ""
for (let i = 0; i <= n/2; i++) {
let k = n - 2 * i
for (let j =0; j < Math.floor(n/2)*2 + 1; j++) {
if(j < Math.floor(n/2) - i) {
string += " ";
}
if( j >= Math.floor(n/2) - i && j <= Math.floor(n/2) + i) {
string += k;
j < Math.floor(n/2) ? k++ : k--
}
if(j > Math.floor(n/2) + i ) {
string += " ";
}
}
string += "\n";
}
console.log(string);
}
p(7);

Related

Why the Double mirror pascal star pattern is not printed?

Here is the my javascript code for printing the pattern shown below in the image.
please check the code and solve the error.
<script>
var n = prompt("Enter the number of n you want to print");
//rows = Math.floor(n / 2)
let str = ""
var i, j, k
for(i = 1; i <= n; i++){
for(j = 1; j <= i; j++){
str += "*"
}
for(k = n + 1; k >= i; k--){
str += " "
}
for(k = n + 1; k >= i; k--){
str += " "
}
for(j = 1; j <= i; j++){
str += "*"
}
str += "\n"
}
for(i = 1; i <=n + 2; i++){
for(j = n + 2; j > i; j--){
str += "*"
}
for(k = 1; k <= i; k++){
str = " "
}
for(k = 1; k <= i; k++){
str = " "
}
for(j = n + 2; j > i; j--){
str += "*"
}
str += "\n"
}
console.log(str)
</script>
I want Output like this :
but I got just 2 spaces in output
Convert your input to Number:
n = Number(n);
and then change your code as #TomLV mentioned:
var n = prompt("Enter the number of n you want to print");
//rows = Math.floor(n / 2)
n = Number(n);
let str = ""
var i, j, k
for(i = 1; i <= n; i++){
for(j = 1; j <= i; j++){
str += "*"
}
for(k = n + 1; k >= i; k--){
str += " "
}
for(k = n + 1; k >= i; k--){
str += " "
}
for(j = 1; j <= i; j++){
str += "*"
}
str += "\n"
}
for(i = 1; i <=n + 2; i++){
for(j = n + 2; j > i; j--){
str += "*"
}
for(k = 1; k <= i; k++){
str += " "
}
for(k = 1; k <= i; k++){
str += " "
}
for(j = n + 2; j > i; j--){
str += "*"
}
str += "\n"
}
console.log(str)
You are setting str equal to " " in both "k loops" in the second "i for loop".
e.g:
for(k = 1; k <= i; k++){
str = " "
}
for(k = 1; k <= i; k++){
str = " "
}
If you update those to += it works.
Some issues:
prompt returns a string, you need to convert it to a number. You can use the unary plus for that.
str = " " occurs at two places where you should have done str += " "
The generated pattern has two spaces in the center line, while you are asked to only have one space there. To make that happen have the k loops make one iteration less, and add str += " " as a separate statement outside of those loops.
The output has an empty line at the very end. This is because the second i loop is making one iteration too many.
Not a problem, but:
Use semi-colons to separate statements. Although JavaScript provides automatic semi-colon insertion, you wouldn't be the first to fall into one of the pitfalls. It is better to take control of this yourself and have the habit of adding the semi-colons.
There really is no need here to declare loop variables at the top. Just declare them at the moment you need them with only the scope they need to have.
I'll assume that the number of lines in the output is supposed to be n*2+1 and that there was no error concerning that aspect.
Corrected code:
// Convert string to number using unary plus:
const n = +prompt("Enter the number of n you want to print");
let str = "";
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= i; j++) {
str += "*";
}
// Reduced the number of iterations here:
for (let k = n; k >= i; k--) {
str += " ";
}
// Add one space for the center column
// that is the only column without asterisks
str += " ";
// Reduced the number of iterations here:
for (let k = n; k >= i; k--) {
str += " ";
}
for (let j = 1; j <= i; j++) {
str += "*";
}
str += "\n";
}
// Reduced number of iterations. i should not become equal to n + 2
for (let i = 1; i <= n + 1; i++) {
for (let j = n + 2; j > i; j--) {
str += "*";
}
// Reduced the number of iterations here:
for (let k = 1; k < i; k++) {
str += " "; // Fixed assignment
}
// Add one space for the center column
// that is the only column without asterisks
str += " ";
// Reduced the number of iterations here:
for (let k = 1; k < i; k++) {
str += " "; // Fixed assignment
}
for (let j = n + 2; j > i; j--) {
str += "*";
}
str += "\n";
}
console.log(str);
Note that JavaScript has functions that can facilitate this proces, like "*".repeat(i) can be used instead of a loop to produce the same string.
So then it becomes:
const n = +prompt("Enter the number of n you want to print");
let str = "";
for (let i = 1; i <= n + 1; i++) {
str += "*".repeat(i) + " ".repeat(2*n + 3 - 2*i) + "*".repeat(i) + "\n";
}
for (let i = n; i >= 1; i--) {
str += "*".repeat(i) + " ".repeat(2*n + 3 - 2*i) + "*".repeat(i) + "\n";
}
console.log(str);
And you could also reuse the results of the first loop to derive the second half of the output by storing the lines in an array. You can then reverse that array to get the second half (without the middle line):
const n = +prompt("Enter the number of n you want to print");
const arr = Array.from({length: n + 1}, (_, i) =>
"*".repeat(i+1) + " ".repeat(2*(n-i)+1) + "*".repeat(i+1)
);
console.log([...arr, ...arr.reverse().slice(1)].join("\n"));

I'm trying to create a star pyramid which should contain 1 * in the first row, 2* with equal spaces in the second row, like wise 3rd and 4th row

[enter image description here][1]
List item
let x = 4;
let text = "";
for(let i = 1; i <= x; i++) {
for(let j = 1; j <= x - i; j++) {
text += " ";
}
for(let k = 0; k < 2 * i - 1; k++) {
text += "*";
}
text +="\n";
}
console.log(text);
---Output I want is like this. I'm new to this. Thank you in advance
[1]: https://i.stack.imgur.com/AJvaZ.png
Small change:
let x = 4;
let text = "";
for(let i = 1; i <= x; i++) {
for(let j = 1; j <= x - i; j++) {
text += " ";
}
text += "*";
for(let k = 0; k + 1 < i; k++) {
text += " *";
}
text +="\n";
}
console.log(text);

Shorter Way of Prinitng Triangle Patterns JavaScript

I'm trying to find a shorter way to print a right-triangle and an isosceles triangle without using that many nested loops. Please help, here is my code so far, it works I just have trouble finding a shorter way to write it:
//right-triangle
let triangleStr = "";
let num = 5;
for (let i = 1; i <= num; i++) {
for (let j = 0; j < num - i; j++) {
triangleStr += " ";
}
for (let k = 0; k < i; k++) {
triangleStr += "*";
}
triangleStr += "\n";
}
console.log(triangleStr);
//isosceles-triangle
triangleString = "";
for (let i = 1; i <= num; i++) {
for (let j = 1; j <= num - i; j++) {
triangleString += " ";
}
for (let k = 1; k <= 2 * i - 1; k++) {
triangleString += "*";
}
triangleString += "\n";
}
console.log(triangleString);
If you want to use only one loop, you can use repeat() method in ECMAScript6 or higher.
For Right triangle:
const line = 5;
let rightTriangle = "";
for (let l = 1; l <= line ; l++) {
const indent = line-l;
rightTriangle += `${" ".repeat(indent)}${"*".repeat(l)}${"\n"}`;
}
console.log(rightTriangle);
For Isosceles triangle:
const line = 5;
let isoscelesTriangle = "";
for (let l = 1; l <= line ; l++) {
const indent = line - l;
isoscelesTriangle += `${" ".repeat(indent)}${"*".repeat(2*l-1)}${"\n"}`;
}
console.log(isoscelesTriangle);

Print pyramid number using JavaScript

I want to create a pyramid number structure. Can anyone explain me how?
for (i = 1; i <= 5; i++) {
var k = ' ';
var myspace = '';
for (j = 0; j < i - 0; j++) {
k += i;
myspace += ' ';
}
console.log(myspace + k);
}
I want make it like this:
1
2 2
3 3 3
4 4 4 4
Try below code:
function createPyramid(rows) {
for (var i = 0; i < rows; i++) {
var output = '';
for (var j = 0; j < rows - i; j++) output += ' ';
for (var k = 0; k <= i; k++) output += (i + 1) + ' ';
console.log(output);
}
}
createPyramid(4);
Try below method.
var a;
var n = 5;
for (var i = 1; i <= n; i++) {
for (var j = 1; j <= i; j++) {
document.write(j + " ");
}
document.write("<br />");
}

Inclined pyramid pattern

I want to create a pyramid-pattern (on the side).
I've gotten the first part, but I need help to count the last part down.
So far I've got this:
var out = document.getElementById("out");
for (var i = 0; i < 20; i++ ){
if ( i <= 10){
for ( var j = 0; j < i; j++ ){
out.innerHTML += "*";
}
} else if (i > 10){
for (var j = 9; j > 0; j--){
out.innerHTML += "*";
}
}
out.innerHTML += "<br>";
}
<p id="out"></p>
You can run a loop from 19-i to 0, and while i increments further the value of 19-i gets smaller and smaller:
var out = document.getElementById("out");
for (var i = 0; i < 20; i++ ){
if ( i <= 10){
for ( var j = 0; j < i; j++ ){
out.innerHTML += "*";
}
} else if (i > 10){
for ( var j = 19-i; j >= 0; j--){ // <-- run loop so that number of iterations gets lower and lower
out.innerHTML += "*";
}
}
out.innerHTML += "<br>";
}
<p id="out"></p>
Simple solution to draw Pyramid shape based on the given steps/count:
var steps = 5, outputStr = "", isTriangle = false;
var newLine = "<br />"; // "\n" for String, <br /> for element break line.
for (var i = 1; i <= steps; i++) {
// Forward
for (var j = 1; j <= i; j++) {
outputStr += i;
}
outputStr += newLine;
if (i == steps && !isTriangle) {
// Backward - After completing Forward
var k = i - 1;
while (k > 0) {
for (var j = k; j > 0; j--) {
outputStr += k;
}
k--;
outputStr += newLine;
}
}
}
var out = document.getElementById("out");
out.innerHTML = outputStr;
<p id="out"></p>
for java see: Draw Pyramid

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