How to convert binary representation to array [Solved]

Question

How would one convert? For example :

int main() {
int num;
cin >> num;
int* x = #
cout << x;

gives output of what needs to be placed into an array. Maybe something like

char* arr ?

I'm kinda lost here :)

To solve a Code Coach called Number of Ones it requires converting x into an array (I think... ).

Can anyone suggest an approach, remembering this challenge is marked as easy and therefore shouldn't require using intermediate+ knowledge?

Thank you, all suggestions welcome!

Answer 1

Is the binary representation a string? If so, you just have to iterate over the string characters and append each corresponding value to the array.
Iterate and append = loop thru string indexes and write the array using the same indexes.
Corresponding value = a translation from ASCII '0' and '1' to the array values (maybe 0 and 1 integers).

Answer 2

Emerson Prado (and anyone who may read this)

I think I found the answer to what I was asking although it uses bitset which I don't remember seeing in the "easy" level of lessons so far.

#include <iostream>
#include <bitset>
using namespace std;

int main() {
int x;
cin >> x;
string str = bitset<8>(x).to_string();
cout << str;
}

Answer 3

Looks like I was able to solve the task. For anyone interested I have linked the code, it passed the Code Coach. And if anyone sees a more "elegant" solution (easy level) I am always appreciative of tips that will help me improve.
https://code.sololearn.com/cPXNlBRf7yCe/?ref=app

Answer 4

Good!
I'd like to suggest one correction and one improvement:

The loop "for (int i = 0; i <16; i++)" limits the input to 2^16-1. For higher numbers, the most significant bits are lost.
Instead of 16, use the string length as limit.

The array "num" and the loop "for (int x = 0; x < 1; x++)" are unnecessary - num[x] is always '1'.
Just compare str[i] to '1'. If you prefer using a variable, make it a char and assign it '1'.

Answer 5

Emerson Prado
Fantastic! Works great, cuts out a few lines of code and looks cleaner.

FWIW, in my first attempt I used a bitset value of 8. It passed 3 of 5 tests and failed two. I played with it a "bit" (excuse the bad pun) and realized using cout << str that if cin x was a larger number then it was returning all "ones". Setting bitset to 16 resolved that. 32 seems even safer.

Thanks again!

P.S. I realize there were 2 options for strlen.
• to use the int method (which I did)
• to instead use "for(unsigned int... str.length()"

Is one more preferable than the other?

Code attached for anyone interested.
https://code.sololearn.com/c5oDAKhcD81S/?ref=app

Answer 6

The second one is a bit less readable, but saves some code and a variable

Answer 7

Emerson Prado
Thank you for the reply. Here is the task.
" Task:
Count the number of ones in the binary representation of a given integer.

Input Format:
An integer.

Output Format:
An integer representing the count of ones in the binary representation of the input.
Sample Input:
9
Sample Output:
2 "

I now realize I was possibly mistaking the binary number for memory address. I am very new to programming but think I know how to solve this if I can understand how to take the given integer and turn it into a binary string or array. I'm getting more familiar with arrays but it takes some time.

I don't yet know how to use C++ to convert an int to binary, perhaps I missed it in an earlier lesson.

Answer 8

Emerson Prado
Thanks! I'll look that over and see if I can actually apply your advice to my current code without breaking it😂