# JavaScript: Reverse a Binary string

## JavaScript String: Exercise-19 with Solution

Write a JavaScript function that takes a positive integer and reverses the binary representation of that integer. Finally return the decimal version of the binary string.
Test Data:
(100) -> 19
Explanation:
Binary representation of 100 is 1100100
Reverse of 1100100 is 10011
Decimal form of 10011 is 19
(1134) -> 945
Explanation:
Binary representation of 1134 is 10001101110
Reverse of 10001101110 is 1110110001
Decimal form of 1110110001 is 945

Sample Solution:

JavaScript Code:

``````function test(n) {
return parseInt(n.toString(2).split('').reverse().join(''), 2);
}
console.log(test(100));
console.log(test(1134));
```
```

Output:

```19
945
```

Explanation:

In the exercise above,

• The function takes an integer 'n' as input.
• It converts the integer n to its binary representation using the "toString(2)" method, which returns a string containing the binary representation of the number.
• It splits the binary string into an array of characters, reverses the order of the characters, and then joins them back into a single string using the "reverse()" and "join('')" methods.
• Finally, it converts the reversed binary string back to an integer using "parseInt(string, 2)", where the second argument specifies that the string is in base 2 (binary).
• The function returns a reversed binary integer.
• The function is tested with different input numbers, and the results are printed to the console.

Flowchart:

Live Demo:

See the Pen javascript-string-exercise-64 by w3resource (@w3resource) on CodePen.

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