how can replace and add to array

[Hawlong]

#include <iostream>
using namespace std;
 
// function to convert decimal to binary
void decToBinary(int n)
{
    // array to store binary number
    int binaryNum[32];
 
    // counter for binary array
    int i = 0;
    while (n > 0) {
 
        // storing remainder in binary array
        binaryNum[i] = n % 2;
        n = n / 2;
        i++;
    }
 
    // printing binary array in reverse order
    for (int j = i - 1; j >= 0; j--)
        cout << binaryNum[j];
}
 
// Driver program to test above function
int main()
{
    int n = 10000;
    decToBinary(n);
    return 0;
}

Output:
10011100010000

I want change out put like this [ by code] :
110111000100010

[lastchance]

Hawlong wrote:

Output:
10011100010000

I want change out put like this [ by code] :
110111000100010

Would you like to have another go at explaining what you want to do.

[seeplus]

Well 10000 decimal is 10011100010000 as binary - so what's the issue?

Do you mean you want the output left filled with 0's like this:

#include <iostream>

// function to convert decimal to binary
void decToBinary(int n) {
	// array to store binary number
	int binaryNum[32] {};

	// counter for binary array
	for (size_t i {}; n > 0; ++i, n /= 2)
		// storing remainder in binary array
		binaryNum[i] = n % 2;

	// printing binary array in reverse order
	for (size_t j = 32; j > 0; --j)
		std::cout << binaryNum[j - 1];
}

// Driver program to test above function
int main() {
	decToBinary(10000);
}

00000000000000000010011100010000

This can also be done simply using std::bitset:

#include <iostream>
#include <bitset>

// function to convert decimal to binary
void decToBinary(unsigned n) {
	std::cout << std::bitset<32> {n} << '\n';
}

// Driver program to test above function
int main() {
	decToBinary(10000);
}

See:
https://cplusplus.com/reference/bitset/bitset/

[Hawlong]

Thanks all for replay ,


I have a packet that comes encrypted from the server
to decode this packet , I convert it to binary and i change some bits ..

Example:
i have this bits : 10011100010000
i want add (1)bit 1001110(1)0010000 and change second bit to (1)
1(1)0111010010000

Thanks ..

[lastchance]

Either use a std::string or a vector<bool>. Then you can corrupt your messages to your heart's content.

[seeplus]

Well changing 100111 to 110111 is easy. Just change the appropriate element in the array. Adding an extra bit is best done with using a std::vector. Or use the std::bitset:

#include <iostream>
#include <bitset>

// function to convert decimal to binary
void decToBinary(unsigned n) {
	constexpr size_t noBits { 16 };
	constexpr size_t inspos { noBits - 8 };

	static_assert (noBits >= 16 && noBits % 8 == 0);

	const auto s { std::bitset<noBits> { n }.to_string() };

	std::bitset<noBits> bar { s.substr(1, inspos) + "1" + s.substr(inspos + 1) };
	bar.set(13, 1);

	std::cout << bar << '\n';
}

// Driver program to test above function
int main() {
	decToBinary(10000);
}

which displays:

0110111010010000

as required.

[Hawlong]

Thanks so much seeplus , solved