Convert bytes array to Hexadecimal String

Question

Here is a that I write for Print a byte array to hex String , but now I want to save them as std::string and use it later

here is my code

typedef std::vector<unsigned char> bytes;
void printBytes(const bytes &in)
{
    std::vector<unsigned char>::const_iterator from = in.begin();
    std::vector<unsigned char>::const_iterator to = in.end();
    for (; from != to; ++from) printf("%02X", *from);
}

what can I do ?, I want to save it as a string not print(Show) in console window? any idea!

"*in C++ there is no function like StringBuilder*" - yes, there is. It's called `std::ostringstream`. — Remy Lebeau, Feb 25 '17 at 01:48

Remy Lebeau · Accepted Answer · 2017-05-25T14:09:54.213

3

Use std::ostringstream:

typedef std::vector<unsigned char> bytes;
std::string BytesToStr(const bytes &in)
{
    bytes::const_iterator from = in.cbegin();
    bytes::const_iterator to = in.cend();
    std::ostringstream oss;
    for (; from != to; ++from)
       oss << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(*from);
    return oss.str();
}

edited May 25 '17 at 14:09

answered Feb 25 '17 at 01:52

Remy Lebeau

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`static_cast()` would be more idiomatic in C++ than the C-style cast `(int)`. – phoenix May 25 '17 at 12:34
If you want to append the `0x` to the front, use [`std::showbase`](http://en.cppreference.com/w/cpp/io/manip/showbase) – phoenix May 25 '17 at 12:36
@phoenix how would you go about converting this string back? – anc Aug 03 '17 at 12:28
1

@anc: you can use `std::hex` and `std::setw()` with `std::istringstream` and `operator>>` – Remy Lebeau Aug 03 '17 at 15:51

Convert bytes array to Hexadecimal String

1 Answers1