158 lines
8.8 KiB
Markdown
158 lines
8.8 KiB
Markdown
|
---
|
||
|
|
title: Binary Agents
|
||
|
|
---
|
||
|
|
|
||
|
|
|
||
|
|
 Remember to use <a>**`Read-Search-Ask`**</a> if you get stuck. Try to pair program  and write your own code 
|
||
|
|
|
||
|
|
## Problem Explanation:
|
||
|
|
|
||
|
|
This problem is very straight forward, you will get a string that will represent a sentence in binary code, and you need to translate that into words. There is not direct way to do this so you will have to translate twice.
|
||
|
|
|
||
|
|
### Relevant Links
|
||
|
|
|
||
|
|
* <a href='http://forum.freecodecamp.com/t/javascript-string-prototype-charcodeat/15933' target='_blank' rel='nofollow'>String.prototype.charCodeAt</a>
|
||
|
|
* <a>String.fromCharCode</a>
|
||
|
|
|
||
|
|
##  Hint: 1
|
||
|
|
|
||
|
|
You should first convert from **binary** to **decimal** before translating those values into characters.
|
||
|
|
|
||
|
|
> _try to solve the problem now_
|
||
|
|
|
||
|
|
##  Hint: 2
|
||
|
|
|
||
|
|
Things are easier when focusing on smaller parts, divide the input to focus on one letter at the time.
|
||
|
|
|
||
|
|
> _try to solve the problem now_
|
||
|
|
|
||
|
|
##  Hint: 3
|
||
|
|
|
||
|
|
Make sure that each time you transcode a character from binary to decimal, you reset whatever variable you used to keep track of the ones. Also do not forget to turn everything back into one string.
|
||
|
|
|
||
|
|
> _try to solve the problem now_
|
||
|
|
|
||
|
|
## Spoiler Alert!
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
**Solution ahead!**
|
||
|
|
|
||
|
|
##  Basic Code Solution:
|
||
|
|
```javascript
|
||
|
|
function binaryAgent(str) {
|
||
|
|
biString = str.split(' ');
|
||
|
|
uniString = [];
|
||
|
|
|
||
|
|
/*using the radix (or base) parameter in parseInt, we can convert the binary
|
||
|
|
number to a decimal number while simultaneously converting to a char*/
|
||
|
|
|
||
|
|
for(i=0;i < biString.length;i++){
|
||
|
|
uniString.push(String.fromCharCode(parseInt(biString[i], 2)));
|
||
|
|
}
|
||
|
|
|
||
|
|
// we then simply join the string
|
||
|
|
return uniString.join('');
|
||
|
|
}
|
||
|
|
|
||
|
|
// test here
|
||
|
|
binaryAgent("01000001 01110010 01100101 01101110 00100111 01110100 00100000 01100010 01101111 01101110 01100110 01101001 01110010 01100101 01110011 00100000 01100110 01110101 01101110 00100001 00111111");
|
||
|
|
```
|
||
|
|
 <a href='https://repl.it/CLnm/0' target='_blank' rel='nofollow'>Run Code</a>
|
||
|
|
|
||
|
|
# Code Explanation:
|
||
|
|
|
||
|
|
* Separate the string into an array of strings separated by whitespace.
|
||
|
|
* Create some variables that will be needed along the way, the names are self explanatory for the most part.
|
||
|
|
* Iterate through each binary string in the new array.
|
||
|
|
* Convert to decimal by using parseInt(_binary_, 2) (with the second parameter we tell in which base our numbers currently are)
|
||
|
|
* At the end, we return out converted message.
|
||
|
|
|
||
|
|
## Relevant Links
|
||
|
|
|
||
|
|
* <a href='http://forum.freecodecamp.com/t/javascript-string-prototype-split/15944' target='_blank' rel='nofollow'>String.prototype.split</a>
|
||
|
|
* <a href='http://forum.freecodecamp.com/t/javascript-parseint/14686' target='_blank' rel='nofollow'>parseInt</a>
|
||
|
|
|
||
|
|
##  Intermediate Code Solution:
|
||
|
|
```javascript
|
||
|
|
function binaryAgent(str) {
|
||
|
|
// Separate the binary code by space.
|
||
|
|
str = str.split(' ');
|
||
|
|
var power;
|
||
|
|
var decValue = 0;
|
||
|
|
var sentence = '';
|
||
|
|
|
||
|
|
// Check each binary number from the array.
|
||
|
|
for (var s = 0; s < str.length; s++) {
|
||
|
|
// Check each bit from binary number
|
||
|
|
for (var t = 0; t < str[s].length; t++) {
|
||
|
|
// This only takes into consideration the active ones.
|
||
|
|
if (str[s][t] == 1) {
|
||
|
|
// This is quivalent to 2 ** position
|
||
|
|
power = Math.pow(2, +str[s].length - t - 1);
|
||
|
|
decValue += power;
|
||
|
|
|
||
|
|
// Record the decimal value by adding the number to the previous one.
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// After the binary number is converted to decimal, convert it to string and store
|
||
|
|
sentence += (String.fromCharCode(decValue));
|
||
|
|
|
||
|
|
// Reset decimal value for next binary number.
|
||
|
|
decValue = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
return sentence;
|
||
|
|
}
|
||
|
|
|
||
|
|
// test here
|
||
|
|
binaryAgent("01000001 01110010 01100101 01101110 00100111 01110100 00100000 01100010 01101111 01101110 01100110 01101001 01110010 01100101 01110011 00100000 01100110 01110101 01101110 00100001 00111111");
|
||
|
|
```
|
||
|
|
 <a href='https://repl.it/CLno/0' target='_blank' rel='nofollow'>Run Code</a>
|
||
|
|
|
||
|
|
# Code Explanation
|
||
|
|
|
||
|
|
* For each of these binary strings, check for the ones and ignore the zeroes.
|
||
|
|
* For those that are one or active then convert them to decimal, this takes into account the position and the right power it needs to be raised to.
|
||
|
|
* Store the power into the **power** variable by adding it to any previous ones on the variable **decValue**. This variable will add and add the powers of the active ones until the end of the loop and then return the decimal number.
|
||
|
|
* Convert the final decimal outside of the inner loop and then convert it to ASCII and saving it to **sentence** along with any other text string already converted and stored.
|
||
|
|
* Reset the variable **decValue** to avoid getting wrong decimals before continuing to the outer loop.
|
||
|
|
|
||
|
|
## Relevant Links
|
||
|
|
|
||
|
|
* <a href='http://forum.freecodecamp.com/t/javascript-math-pow/14685' target='_blank' rel='nofollow'>Math.pow</a>
|
||
|
|
* <a>String.length</a>
|
||
|
|
* <a href='http://example.com' target='_blank' rel='nofollow'>Link Title 3</a>
|
||
|
|
|
||
|
|
##  Advanced Code Solution:
|
||
|
|
```javascript
|
||
|
|
function binaryAgent(str) {
|
||
|
|
return String.fromCharCode(...str.split(" ").map(function(char){ return parseInt(char, 2); }));
|
||
|
|
}
|
||
|
|
|
||
|
|
// test here
|
||
|
|
binaryAgent("01000001 01110010 01100101 01101110 00100111 01110100 00100000 01100010 01101111 01101110 01100110 01101001 01110010 01100101 01110011 00100000 01100110 01110101 01101110 00100001 00111111");
|
||
|
|
```
|
||
|
|
 <a href='https://repl.it/CLnp/0' target='_blank' rel='nofollow'>Run Code</a>
|
||
|
|
|
||
|
|
# Code Explanation
|
||
|
|
|
||
|
|
* First we use `split()` to be able to work on each character as an Array element
|
||
|
|
* Then use `map()` to process each element from binary to decimal using `pareseInt()`
|
||
|
|
* Last we can use `String.fromCharCode()` to convert each ASCII number into the corresponding character
|
||
|
|
* However `fromCharCode()` expects a series of numbers rather than an Array! We can use ES6 Spread Operator to pass in an Array of numbers as individual numbers. See here for more info; <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator' target='_blank' rel='nofollow'>Spread Operator</a>
|
||
|
|
|
||
|
|
## Relevant Links
|
||
|
|
|
||
|
|
* <a href='http://forum.freecodecamp.com/t/javascript-array-prototype-map/14294' target='_blank' rel='nofollow'>Array.prototype.map</a>
|
||
|
|
|
||
|
|
##  NOTES FOR CONTRIBUTIONS:
|
||
|
|
|
||
|
|
*  **DO NOT** add solutions that are similar to any existing solutions. If you think it is **_similar but better_**, then try to merge (or replace) the existing similar solution.
|
||
|
|
* Add an explanation of your solution.
|
||
|
|
* Categorize the solution in one of the following categories — **Basic**, **Intermediate** and **Advanced**. 
|
||
|
|
* Please add your username only if you have added any **relevant main contents**. ( **_DO NOT_** _remove any existing usernames_)
|
||
|
|
|
||
|
|
> See  <a href='http://forum.freecodecamp.com/t/algorithm-article-template/14272' target='_blank' rel='nofollow'>**`Wiki Challenge Solution Template`**</a> for reference.
|