JavaScript Program to Print Pyramid Pattern by using Numbers
Last Updated :
16 Jan, 2024
A pyramid pattern using numbers is a sequence of numbers arranged in a triangular shape, with each row displaying incrementing or decrementing numbers, creating a visually structured pattern.
Example:
1
1 2 3
1 2 3 4 5
1 2 3 4 5 6 7
1 2 3 4 5 6 7 8 9
Approach
- We initialize a variable n with the value 5. This variable determines the number of rows in the pattern.
- We use a for loop with the variable i to iterate from 1 to n (inclusive). This loop controls the rows of the pattern.
- Inside the outer loop, there’s another for loop with the variable j, iterating from 1 to 2 * n (twice the number of columns). This loop controls the columns of the pattern.
- we use Conditional logic to checks if (i + j >= n + 1 && i >= j – n + 1) for number or gap. Numbers increment; otherwise, two spaces are added.
- After the inner loop, print str (one row). Repeat for each i, forming the desired pattern.
Example 1: We are using the above-explained approach.
Javascript
let n = 5;
for (let i = 1; i <= n; i++) {
let str = '' ;
let count = 1;
for (let j = 1; j <= 2 * n; ++j) {
if (i + j >= n + 1 && (i >= j - n + 1)) {
str += count.toString() + ' ' ;
count++;
} else {
str += ' ' ;
}
}
console.log(str);
}
|
Output
1
1 2 3
1 2 3 4 5
1 2 3 4 5 6 7
1 2 3 4 5 6 7 8 9
Example 2: We are making Pyramid pattern by using number in left direction.
Javascript
let n = 5;
for (let i = 1; i <= n; i++) {
let str = '' ;
let count = 1;
for (let j = 1; j <= n; ++j) {
if (i + j >= 1 + n && j <= n) {
str += count.toString() + ' ' ;
count += 1;
} else {
str += ' ' ;
}
}
console.log(str);
};
for (let i = n - 1; i >= 1; i--) {
let str = '' ;
let count = 1;
for (let j = 1; j <= n; ++j) {
if (i + j >= 1 + n && j <= n) {
str += count.toString() + ' ' ;
count += 1;
} else {
str += ' ' ;
}
}
console.log(str);
};
|
Output
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5
1 2 3 4
1 2 3
1 2
1
Example 3: We are making Pyramid pattern by using numbers in right direction.
Javascript
let n = 5;
for (let i = 1; i <= n; i++) {
let str = "" ;
let count = 1;
for (let k = 1; k <= i; k++) {
str = count.toString() + " " + str;
count += 1;
}
for (let j = i; j < n; j++) {
str += " " ;
}
console.log(str);
}
for (let i = n - 1; i >= 1; i--) {
let str = "" ;
let count = 1;
for (let k = 1; k <= i; k++) {
str = count.toString() + " " + str;
count += 1;
}
for (let j = i; j < n; j++) {
str += " " ;
}
console.log(str);
};
|
Output
1
2 1
3 2 1
4 3 2 1
5 4 3 2 1
4 3 2 1
3 2 1
2 1
1
Example 4: We are generated number pyramid in down-ward direction.
Javascript
let n = 5;
for (let i = n; i >= 1; i--) {
let str = '' ;
let count = 1;
for (let j = 1; j <= 2 * n; ++j) {
if (i + j >= n + 1 && (i >= j - n + 1)) {
str += count.toString() + ' ' ;
count++;
} else {
str += ' ' ;
}
}
console.log(str);
};
|
Output
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7
1 2 3 4 5
1 2 3
1
Example 5: We are generating Inverted Half Pyramid
Javascript
function printInvertedHalfPyramid(rows) {
for (let i = rows; i >= 1; i--) {
let row = '' ;
for (let j = 1; j <= i; j++) {
row += j + ' ' ;
}
console.log(row);
}
}
printInvertedHalfPyramid(5);
|
Output
1 2 3 4 5
1 2 3 4
1 2 3
1 2
1
Share your thoughts in the comments
Please Login to comment...