How to display pyramid using JavaScript?

Question

Here is the code to display pyramid but its not exactly producing required output.

相关标签:

Answer 1

**You can FRAME for loop conditions for any patterns given either it may be a triangle, right-angled triangle, inverse triangle, etc.. For more info refer the below code and workbook image. PS: in work book image in step 6 it is 2 + i and not 3+i therefore j >= 4 - i && j <= 2 + i for any number of rows n formula is : j >= n+1 - i && j <= n - 1 + i **

1, 3, 5, 7, 9 => Odd number series (stars) appear in pyramid pattern
1, 2, 3, 4, 5 => Counter (number of rows)

For each counter there exist (2 * n) - 1 value

    function pyramid(n) {  // Input or number of rows
        for (var i = 1; i <= n; i++) {
            var s = "";
            // For every each counter there exist 2*n-1 value
            for (var j = 1; j <= (2 * n - 1); j++) {
              // Hint: Check the workbook image
                (j >= n + 1 - i && j <= n - 1 + i) ? s += "*" : s += " ";   
            }
            console.log(s);
        }
    }
    pyramid(5);

For your requirements, the following code should be fine:

    function generateNumberTriangle(v) {
    for (var i = 1; i <= v; i++) {
        var chars = " ";
        for (var j = 1; j <= v; j++) {
            if (j <= i) { chars += j + "  "; }
        }
        console.log(chars);
    }
}
generateNumberTriangle(7);

Answer 2

Simple code of Number Pyramid

for(var i=1; i<=5; i++){
 var Num='';
 for(var j=0; j<i; j++){
     Num += i;
 }
 print(Num) }

Answer 3

Assuming you want to return numbers and not asterisks as the other answers show, here is that solution:

Note that this solution runs in linear (O(n)) time complexity and doesn't sacrifice performance by logging every line to the console, but the entire pyramid at once instead.

function generatePyramid(n) {
  let pyramid = '';
  let prev;

  for (let i = 1; i <= n; i++) {
    if (prev) {
      pyramid += '\n';
      prev =  prev + ' ' + i;
    } else {
      prev = i;
    }
    pyramid += ' '.repeat(n - i) + prev;
  }

  return pyramid;
}

Log to the console as such: console.log(generatePyramid(n));

If you're looking to just draw a triangle as the picture in your question shows, this function will do that (again, in linear time complexity):

function drawTriangle(n) {
  let triangle = '';
  let prev;
  for (let i = 1; i <= n; i++) {
    if (prev) {
      triangle += '\n';
      prev = prev + ' ' + i;
    } else {
      prev = i;
    }
    triangle += prev;
  }
  return triangle;
}

Answer 4

If you want to print out a right angle triangle using symbols or single digits. You can use the following code.

let pyramid = '';
for(pyramid.length=0; pyramid.length<=7 ; pyramid+='#'){
  console.log(pyramid);
}

Answer 5

Why not this ?

let printPyramid = (n) => {
    if (n===0) {
        return false;
    } else {
        let arr = [];
        for(let i=0; i<n; i++) {
           arr.push(i);
           console.log(arr.toString());
        }
    }
}

Answer 6

You should generate an array on every row iteration and output it at the end:

function generatePyramid() {
    var totalNumberofRows = 5,
        arr;
    for (var i = 1; i <= totalNumberofRows; i++) {
        arr = [];
        for (var j = 1; j <= i; j++) {
            arr.push(j);            
        }
        console.log(arr.join(" ") + "\n");
    }
}