Convert a string of binary into an ASCII string (C++)

Question

I have a string variable containing 32 bits of binary. What would be the best way to convert these 4 characters (8 bits is one character) represented by the binary back into their ASCII characters?

For example, a variable contains "01110100011001010111001101110100" which should be converted back into the string "test".

Answer 1

Try using this with method. Example:

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

string BinaryStringToText(string binaryString) {
    string text = "";
    stringstream sstream(binaryString);
    while (sstream.good())
    {
        bitset<8> bits;
        sstream >> bits;
        text += char(bits.to_ulong());
    }
    return text;
}

int main()
{
    string binaryString = "0100100001100101011011000110110001101111001000000101011101101111011100100110110001100100";
    cout << "Binary string: " << binaryString << "!\n";
    cout << "Result binary string to text: " << BinaryStringToText(binaryString) << "!\n";

    return 0;
}

result code:

Binary string: 0100100001100101011011000110110001101111001000000101011101101111011100100110110001100100!                                                                                                  
Result binary string to text: Hello World! 

Answer 2

An alternative if you're using C++11:

#include <iostream>
#include <string>
#include <sstream>
#include <bitset>

int main()
{
    std::string data = "01110100011001010111001101110100";
    std::stringstream sstream(data);
    std::string output;
    while(sstream.good())
    {
        std::bitset<8> bits;
        sstream >> bits;
        char c = char(bits.to_ulong());
        output += c;
    }

    std::cout << output;

   return 0;
}

Note that bitset is part of C++11.

Also note that if data is not well formed, the result will be silently truncated when sstream.good() returns false.