Concatanation of strings and ints in C++. Conversion from ASCII to HEX

Question

I've been banging my head against the wall trying lots of different methods for doing this but none of them seem to work correctly.

The commented out lines are the code in C# that i'm trying to re-write in C++. Any help would be much appreciated.

void sendCommand(string command)
{
    //Convert.ToString((8 * startBit) + "4" + command);
    char buffer[50];
    sprintf(buffer, "%d", (8 * startBit));
    motor.printf("sendBuffer: %d\r\n", buffer);
    startBit = 1 - startBit;
    motor.printf("%s%c%s\n\r", buffer, "4", command);
    return;
}

string strAcceleration(int acceleration)
{
    //string accelerationHex = acceleration.ToString("X");
    //accelerationHex = accelerationHex.PadLeft(8,'0');
    char buffer[50];
    sprintf(buffer, "%00000000X", acceleration);
    motor.printf("acc: %s", buffer);
    return buffer;
}

string strSpeed(int speed)
{
/*
    string speedHex = null;
    if (speed == 0) speedHex = "0";
    else if (speed > 0) speedHex = speed.ToString("X");
    else speedHex = 0xFFFFFFFF + speed.ToString("X");

    if(speedHex.Length == 1) speedHex = "0000000" + speedHex;
    if(speedHex.Length == 2) speedHex = "000000" + speedHex;
    if(speedHex.Length == 3) speedHex = "00000" + speedHex;

    return speedHex;

    */
}

Thanks

Joe

Answer 1

I don't know exactly what your C# code does but for the second

sprintf(buffer, "%08X", acceleration);

doesn't look a million miles away. Similarly for the first

std::ostringstream buffer;
buffer << (8 * startBit) <<  "4" << command;
std::string motor = buffer.str();

looks like it's close to what you want.