将 unsigned char* 数组转换为 std::string

Question

I'm using this code to convert the unsigned char* (points to an array of 256 values) to std::string:

int ClassA::Func(unsigned char *dataToSend, int sendLength)
{
    std::stringstream convertStream;
    std::string dataToSendStr = "";

    for(int i=0; i<=sendLength; i++) convertStream << dataToSend[i];    

    while(!convertStream.eof()) convertStream >> dataToSendStr;
    ...
}

but then I have dataToSendStr in this format:

dataToSendStr "" 
[0]           0x00 
[1]           0x00 
[2]           0x04 
[3]           0xC0

if I now use this value I only get "" and not the important values [0-3]!

-> need something like: dataToSendStr "000004C0"

Thx for your help!

Answer 1

Use the IO manipulator std::hex if you want (which is what I think based on the need something like part of the question) a hexadecimal representation of the characters in dataToSend :

std::ostringstream convertStream;
convertStream << std::hex << std::setfill('0');

for (int i = 0; i < sendLength; i++)
{
    convertStream << std::setw(2) << static_cast<short>(dataToSend[i]);
}