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7. Loops & Iterations
1. Print Numbers from 1 to N
Using for
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
document.write(i + " ");
}
</script>
Using while
<script>
let n = 5, i = 1;
while (i <= n) {
document.write(i + " ");
i++;
}
</script>
Using while
<script>
let n = 5, i = 1;
while (i <= n) {
document.write(i + " ");
i++;
}
</script>
Using do…while
<script>
let n = 5, i = 1;
do {
document.write(i + " ");
i++;
} while (i <= n);
</script>
2. Print Numbers from N to 1
Using for
<script>
let n = 5;
for (let i = n; i >= 1; i--) {
document.write(i + " ");
}
</script>
Using while
<script>
let n = 5;
while (n >= 1) {
document.write(n + " ");
n--;
}
</script>
Using do…while
<script>
let n = 5;
do {
document.write(n + " ");
n--;
} while (n >= 1);
</script>
3. Sum of First N Natural Numbers
Using for
<script>
let n = 5, sum = 0;
for (let i = 1; i <= n; i++) sum += i;
document.write(sum);
</script>
Using while
<script>
let n = 5, sum = 0, i = 1;
while (i <= n) {
sum += i;
i++;
}
document.write(sum);
</script>
Using do…while
<script>
let n = 5, sum = 0, i = 1;
do {
sum += i;
i++;
} while (i <= n);
document.write(sum);
</script>
4. Multiplication Table
Using for
<script>
let n = 5;
for (let i = 1; i <= 10; i++) {
document.write(`${n} x ${i} = ${n*i}<br>`);
}
</script>
Using while
<script>
let n = 5, i = 1;
while (i <= 10) {
document.write(`${n} x ${i} = ${n*i}<br>`);
i++;
}
</script>
Using do…while
<script>
let n = 5, i = 1;
do {
document.write(`${n} x ${i} = ${n*i}<br>`);
i++;
} while (i <= 10);
</script>
5. Factorial of a Number
Using for
<script>
let n = 5, fact = 1;
for (let i = 1; i <= n; i++) fact *= i;
document.write(fact);
</script>
Using while
<script>
let n = 5, fact = 1;
while (n > 0) {
fact *= n;
n--;
}
document.write(fact);
</script>
Using do…while
<script>
let n = 5, fact = 1;
do {
fact *= n;
n--;
} while (n > 0);
document.write(fact);
</script>
6. Fibonacci Series
Using for
<script>
let a = 0, b = 1;
for (let i = 1; i <= 10; i++) {
document.write(a + " ");
[a, b] = [b, a + b];
}
</script>
Using while
<script>
let a = 0, b = 1, i = 1;
while (i <= 10) {
document.write(a + " ");
[a, b] = [b, a + b];
i++;
}
</script>
Using do…while
<script>
let a = 0, b = 1, i = 1;
do {
document.write(a + " ");
[a, b] = [b, a + b];
i++;
} while (i <= 10);
</script>
7. Reverse a Number
Using for
<script>
let num = 1234, rev = 0;
for (; num > 0; num = Math.floor(num / 10)) {
rev = rev * 10 + num % 10;
}
document.write(rev);
</script>
Using while
<script>
let num = 1234, rev = 0;
while (num > 0) {
rev = rev * 10 + num % 10;
num = Math.floor(num / 10);
}
document.write(rev);
</script>
Using do…while
<script>
let num = 1234, rev = 0;
do {
rev = rev * 10 + num % 10;
num = Math.floor(num / 10);
} while (num > 0);
document.write(rev);
</script>
8. Check Palindrome Number
Using for
<script>
let num = 121, temp = num, rev = 0;
for (; temp > 0; temp = Math.floor(temp / 10)) {
rev = rev * 10 + temp % 10;
}
document.write(num === rev ? "Palindrome" : "Not Palindrome");
</script>
Using while
<script>
let num = 121, temp = num, rev = 0;
while (temp > 0) {
rev = rev * 10 + temp % 10;
temp = Math.floor(temp / 10);
}
document.write(num === rev ? "Palindrome" : "Not Palindrome");
</script>
Using do…while
<script>
let num = 121, temp = num, rev = 0;
do {
rev = rev * 10 + temp % 10;
temp = Math.floor(temp / 10);
} while (temp > 0);
document.write(num === rev ? "Palindrome" : "Not Palindrome");
</script>
9. Count Digits in a Number
Using for
<script>
let num = 12345, count = 0;
for (; num > 0; num = Math.floor(num / 10)) count++;
document.write(count);
</script>
Using while
<script>
let num = 12345, count = 0;
while (num > 0) {
count++;
num = Math.floor(num / 10);
}
document.write(count);
</script>
Using do…while
<script>
let num = 12345, count = 0;
do {
count++;
num = Math.floor(num / 10);
} while (num > 0);
document.write(count);
</script>
10. Check Prime Number
Using for
<script>
let num = 7, prime = true;
for (let i = 2; i <= Math.sqrt(num); i++) {
if (num % i === 0) {
prime = false;
break;
}
}
document.write(prime ? "Prime" : "Not Prime");
</script>
Using while
<script>
let num = 7, i = 2, prime = true;
while (i <= Math.sqrt(num)) {
if (num % i === 0) {
prime = false;
break;
}
i++;
}
document.write(prime ? "Prime" : "Not Prime");
</script>
Using do…while
<script>
let num = 7, i = 2, prime = true;
do {
if (num % i === 0) {
prime = false;
break;
}
i++;
} while (i <= Math.sqrt(num));
document.write(prime ? "Prime" : "Not Prime");
</script>
11. Programs: forEach and for…of
Using forEach
<script>
let numbers = [1, 2, 3, 4, 5];
numbers.forEach(function(n) {
document.write(n + " ");
});
</script>
Using for…of
<script>
let numbers = [10, 20, 30, 40];
for (let n of numbers) {
document.write(n + " ");
}
</script>
12. Programs: Pattern Making
1. Number Square Pattern
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= n; j++) {
document.write(j + " ");
}
document.write("<br>");
}
</script>
2. Number Square (Same Number in Each Row)
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
4 4 4 4 4
5 5 5 5 5
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= n; j++) {
document.write(i + " ");
}
document.write("<br>");
}
</script>
3. Right-Angled Number Triangle
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= i; j++) {
document.write(j + " ");
}
document.write("<br>");
}
</script>
4. Number Triangle (Same Number per Row)
1
2 2
3 3 3
4 4 4 4
5 5 5 5 5
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= i; j++) {
document.write(i + " ");
}
document.write("<br>");
}
</script>
5. Inverted Number Triangle
1 2 3 4 5
1 2 3 4
1 2 3
1 2
1
<script>
let n = 5;
for (let i = n; i >= 1; i--) {
for (let j = 1; j <= i; j++) {
document.write(j + " ");
}
document.write("<br>");
}
</script>
6. Floyd’s Triangle
1
2 3
4 5 6
7 8 9 10
<script>
let n = 4;
let num = 1;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= i; j++) {
document.write(num + " ");
num++;
}
document.write("<br>");
}
</script>
7. Binary Number Pattern
1
0 1
1 0 1
0 1 0 1
<script>
let n = 4;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= i; j++) {
document.write((i + j) % 2 + " ");
}
document.write("<br>");
}
</script>
8. Palindrome Number Triangle
1
2 1 2
3 2 1 2 3
4 3 2 1 2 3 4
<script>
let n = 4;
for (let i = 1; i <= n; i++) {
for (let j = i; j >= 1; j--) {
document.write(j + " ");
}
for (let j = 2; j <= i; j++) {
document.write(j + " ");
}
document.write("<br>");
}
</script>
9. Pyramid Number Pattern
1
2 2
3 3 3
4 4 4 4
<script>
let n = 4;
for (let i = 1; i <= n; i++) {
for (let s = 1; s <= n - i; s++) {
document.write(" ");
}
for (let j = 1; j <= i; j++) {
document.write(i + " ");
}
document.write("<br>");
}
</script>
10. Reverse Number Triangle
5
5 4
5 4 3
5 4 3 2
5 4 3 2 1
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = n; j >= n - i + 1; j--) {
document.write(j + " ");
}
document.write("<br>");
}
</script>
11. Square Star Pattern
*****
*****
*****
*****
*****
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= n; j++) {
document.write("*");
}
document.write("<br>");
}
</script>
12. Right-Angled Triangle (Left Aligned)
*
* *
* * *
* * * *
* * * * *
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= i; j++) {
document.write("* ");
}
document.write("<br>");
}
</script>
13. Inverted Right-Angled Triangle
* * * * *
* * * *
* * *
* *
*
<script>
let n = 5;
for (let i = n; i >= 1; i--) {
for (let j = 1; j <= i; j++) {
document.write("* ");
}
document.write("<br>");
}
</script>
14. Right-Angled Triangle (Right Aligned)
*
* *
* * *
* * * *
* * * * *
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let s = 1; s <= n - i; s++) {
document.write(" ");
}
for (let j = 1; j <= i; j++) {
document.write("* ");
}
document.write("<br>");
}
</script>
15. Pyramid Star Pattern
*
* * *
* * * * *
* * * * * * *
* * * * * * * * *
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let s = 1; s <= n - i; s++) {
document.write(" ");
}
for (let j = 1; j <= i; j++) {
document.write("* ");
}
document.write("<br>");
}
</script>
16. Inverted Pyramid
*********
*******
*****
***
*
<script>
let n = 5;
for (let i = n; i >= 1; i--) {
for (let s = 1; s <= n - i; s++) {
document.write(" ");
}
for (let j = 1; j <= (2 * i - 1); j++) {
document.write("*");
}
document.write("<br>");
}
</script>
17. Diamond Star Pattern
*
***
*****
***
*
<script>
let n = 3;
// Upper pyramid
for (let i = 1; i <= n; i++) {
for (let s = 1; s <= n - i; s++) document.write(" ");
for (let j = 1; j <= 2*i-1; j++) document.write("*");
document.write("<br>");
}
// Lower inverted pyramid
for (let i = n - 1; i >= 1; i--) {
for (let s = 1; s <= n - i; s++) document.write(" ");
for (let j = 1; j <= 2*i-1; j++) document.write("*");
document.write("<br>");
}
</script>
18. Hollow Square
*****
* *
* *
* *
*****
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= n; j++) {
if (i === 1 || i === n || j === 1 || j === n)
document.write("*");
else
document.write(" ");
}
document.write("<br>");
}
</script>
19. Hollow Triangle
*
* *
* *
* *
*****
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= i; j++) {
if (i === n || j === 1 || j === i)
document.write("*");
else
document.write(" ");
}
document.write("<br>");
}
</script>
20. X Pattern
* *
* *
*
* *
* *
<script>
let n = 5;
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= n; j++) {
if (j === i || j === n - i + 1)
document.write("*");
else
document.write(" ");
}
document.write("<br>");
}
</script>