Hello everyone i have a problem with my code and i'm not sure how to do this , i need to write code that draw this in console:
Draw '*' in every even number
For that i need to use nested loops.
So far i have only this:
var n = 5;
var stars = '';
for (var i = 1; i <= n; i++) {
var starsline = '';
for (var j = 1; j <= n; j++) {
console.log(i + j);
}
if ( i % 2 === 0){
starsline += '2';
} else {
starsline += '1'
}
stars += starsline;
}
console.log(stars);
This numbers 2 and 1 are only to check if the number is even or odd.
Just a few things:
1) you got some weird bracket here:
/*}*/ if ( i % 2 === 0){
which causes a syntax error later on.
2) you actually log the right thing:
console.log(i + j)
but you dont use it. Just put that into your condition:
if((i + j) % 2 === 0)
and you are done :)
let size = 5, stars = "";
for (var row = 1; row <= size; row++) {
var starsline = "";
for (var col = 1; col <= size; col++){
if ((row + col) % 2 === 0){
starsline += '*';
} else {
starsline += ' ';
}
stars += starsline + "\n";
}
console.log(stars);
I think what you tried to do is something like this:
var n = 5;
var stars = '';
for (var i = 1; i <= n; i++) {
var starsline = '';
for (var j = 1; j <= n; j++){
if ( (i + j) % 2 === 0){
// used three spaces for consistency in the drawing
starsline += ' ';
} else {
starsline += ' * '
}
}
stars += starsline + '\n';
}
console.log(stars);
Try this:
var n = 5;
var stars = '';
for (var i = 1; i <= n; i++)
{
var starsline = '';//<-- reset the value of line
if ( i % 2 === 0)//<--this identifies which line will the stars be created
{
starsline += '* * *';//<--creating the stars on each line
}
else
{
starsline += ' * * ';//<--creating the stars on each line
}
stars += starsline+'\n';//<-- '\n' add line breaks for each lines
}
console.log(stars);//<-- print the stars
Related
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 have a problem in JavaScript programing. I am beginner and from last 24 hrs I just completed one task that made pyramid star pattern which only work in console but the problem is this, that the same coding doesn't work on browser. In the browser the triangle become 📐 such type of triangle.
I added br to code for the browser but the triangle become 📐 right angle triangle.
use pre tag to render your result, so it doesn't remove extra spaces. most html tag will remove extra spaces because it thinks those are useless.
let starCount = 1;
const row = 35
let result = "";
for (let i = 0; i < row; i++) {
let starString = "";
const p = starCount;
for (let j = 0; j < row; j++) {
if (j >= ((row - p) / 2) && j < (((row - p) / 2) + p)) {
starString += "*";
continue;
}
starString += " "
}
result += starString + "\n";
if (row % 2 == 0) {
if (i < (row / 2) - 1) {
starCount += 2;
}
if (i > ((row / 2) - 1)) {
starCount -= 2;
}
} else {
if (i < Math.floor(row / 2)) {
starCount += 2;
} else {
starCount -= 2;
}
}
}
document.querySelector("pre").innerHTML = result;
<pre></pre>
I am currently trying to solve the xmas tree problem, with internal tree-like shape.
issue is with internal spacing, it supposed to be like: 1, 5, 7, 9. Instead it is 1, 3, 4, 5. I do not know, how to increment s loop by 2 in each loop turn.
/*
*********
**** ****
*** ***
** **
* *
*********
*/
function drawTree(h) {
let n = h + 3;
for (var i = 1; i <= 1; i++) {
var temp = "";
for (var j = 1; j <= n; j++) {
temp = temp + "*";
}
console.log(temp);
}
for (var i = 0; i < h - 2; i++) {
var tree = '';
console.log("\n");
for (var k = 3; k <= h - i; k++) {
tree += "*";
};
tree += "s";
for (var k = 1; k <= i; k++) {
for (var k = 1; k <= i; k++) {
tree += "s";
};
tree += "s";
};
for (var k = 3; k <= h - i; k++) {
tree += "*";
};
console.log(tree);
};
console.log("\n");
let g = h + 3;
for (var i = 1; i <= 1; i++) {
var temp = "";
for (var j = 1; j <= g; j++) {
temp = temp + "*";
}
console.log(temp);
}
};
drawTree(6);
function drawTree(stars, rowLength) {
for (let row = 0; row < rowLength; row++) {
if (row === 0) {
console.log("*".repeat(stars));
} else if(row === rowLength - 1) {
console.log("*".repeat(stars));
} else {
let spaces = 2 * row - 1;
if (spaces > stars) {
spaces = stars;
}
let numStarsInRow = "*".repeat((stars - spaces) / 2);
console.log(numStarsInRow + " ".repeat(spaces) + numStarsInRow);
}
}
}
drawTree(9, 5)
You can implement this by nesting loops over the height and the width of the tree, noting that the output is a * whenever:
it's the first or last row; or
the current x position is less than or equal to the halfway point minus the row number; or
the current x position is greater than or equal to the halfway point plus the row number
For all other cases the output is a space. For example:
function drawTree(height) {
// compute the width of the tree from the height
let width = height % 2 ? height + 2 : height + 3;
// find the halfway point
let half = (width - 1) / 2;
for (let i = 0; i < height; i++) {
let l = '';
for (let j = 0; j < width; j++) {
if (i == 0 || // first row
i == height - 1 || // last row
j <= (half - i) || // left side
j >= (half + i) // right side
) {
l += '*';
}
else {
l += ' ';
}
}
console.log(l);
}
}
drawTree(6);
drawTree(5);
I'm trying to create a simple algorithm that builds an array with a dynamic length.
Then, it will, one by one, replace an item, and then two, then three and so on until the only items left are the first and last.
like this:
12345
1*345 // it never touches the first
12*45
123*5 // it doesn't ever touch the last item
1**45
12**5
1***5 // done, nowhere else to go
I put together a simple demo to show what I'm trying to do.
var length = 6,
array = [],
log = document.getElementById("log"),
edited,
j,
i;
for (i = 1; i <= length; i++) {
array.push(i);
}
log.innerHTML += array.join(" ") + "<br><br>";
for (i = 1; i < (length - 1); i++) {
edited = array.concat();
for (j = i; j < (length - 1); j++) {
edited[j] = "*";
log.innerHTML += edited.join(" ") + "<br>";
}
log.innerHTML += "<br>";
}
Fiddle
It works fine, the only problem is it's out of order.
Right now it seems to only iterate by number of asterisks, then by index. I need it to do the opposite.
// it does this
12345
1*345
1**45
1***5
12*45
12**5
123*5 // out of order
If someone could help that would be great because I am really at a loss!
This should get it done.
var a = 6, // array length
b = [], // array
log = document.getElementById("log"),
c,
d,
e;
for (c = 1; c <= a; c++) {
b.push(c);
}
log.innerHTML += b.join(" ") + "<br><br>";
//the size of the asterisk chunk
for(i = 1; i < b.length - 1; i ++)
{
//position to start asterisk chunk
for(j = 1; j < b.length - i; j ++)
{
var tempArr = b.concat();
//the position inside of the asterisk chunk
for(k = 0; k < i; k ++)
{
tempArr[k + j] = "*";
}
log.innerHTML += tempArr.join(" ") + "<br>";
}
}
JSFiddle
This seems to work well:
str = "1234567"
len = str.length;
for(var stars = 1; stars < len - 1; stars++) {
for(var pos = 1; pos < len - stars; pos++) {
var s = str.substr(0, pos)
+ new Array(stars + 1).join("*")
+ str.substr(pos + stars);
document.write(s + "<br>");
}
}
I was trying to find the Rank of the given string in the list of permutations and was hoping someone can find the bug.
function permute() {
var W = $('input').val(),
C = [];
for (var i = 0; i < 26; i++) C[i] = 0;
var rank = 1;
for (var i = 0; i < W.length; i++) {
C[W.charCodeAt(i) - 'a'.charCodeAt(0)]++;
}
var repeated= 1;
for (var i = 0; i < C.length; i++) {
if(C[i] > 0) {
repeated *= fact(C[i]);
}
}
if (W !== '') {
for (var i = 0; i < W.length; i++) {
//How many characters which are not used, that come before current character
var count = 0;
for (var j = 0; j < 26; j++) {
if (j == (W.charCodeAt(i) - 'a'.charCodeAt(0))) break;
if (C[j] > 0) count++;
}
C[W.charCodeAt(i) - 'a'.charCodeAt(0)] = 0;
rank += ( count * fact(W.length - i - 1) );
}
rank = rank/ repeated;
}
var pp = 'Rank of :: ' + W + ' -- ' + rank;
$('div').append('<p>' + pp + '</p>');
}
function fact(n) {
if (n == 0 || n == 1) return 1;
else return fact(n - 1) * n;
}
$('button').click(permute);
Check Fiddle
A use case for this might be
bookkeeper is supposed to give a rank of 10743.
Here's the demo:
For each position check how many characters left have duplicates, and use the logic that if you need to permute n things and if 'a' things are similar the number of permutations is n!/a!