Print string without escaping characters

Question

This code:

void Controller::write(const std::string& str) {
    std::cout << "Writing: [" << str << "] to board." << std::endl; 
    s.write(str);

takes a string and pushes it over a serial link to a microcontroller. (This works fine). However, when I try to push a like this: write("ats203?\r"), the console output looks like this:

] to board.ts203?

So the Writing: [a gets overwritten by the ] to board. after std::cout encounters the \r in the string.

How can I print the string as a bunch of characters rather than mangling console output when an escape character is encountered?

EDIT: To clarify.

I want my string to be ats203?\r. This is because the microcontroller is controlled using a slightly modified version of an AT command, and doesn't accept the command until it reads a \r. When the string is pushed to the microcontroller, it reads the \r as a carriage return, and acts on things it read prior to the \r.

What I want is to display the string that I've constructed. There is a bunch of other commands elsewhere that get created depending on flags that are set at runtime. So I end up with strings that look something like ate1\ratv0\rat+OSA=7\rat+OSX=255\r.

I would like to see what I've constructed and what I'm pushing. I can't do this, because std::cout reads the carriage return, acts on it, and mangles my console output.

EDIT: Clarification, again: I want std::cout << "Writing: [" << str << "] to board." << std::endl; to produce (when str is ats203?\r):

Writing: [ats203?\r] to board. 

Answer 1

void Controller::write(const std::string& command_string) {

    std::string display_string = std::regex_replace(command_string,std::regex("(\r)"),"\\r");

    std::cout << "Writing: [" << display_string << "] to board.\n"; 
    s.write(command_string);

So then write("ats203?\r") will literally print out

ats203?\r

Answer 2

Here's a quick loop to generate a readable string.

std::string str2;
for (int i = 0;  i < str.length();  ++i)
{
    if (str[i] == '\r')
    {
        str2.push_back('\\');
        str2.push_back('r');
    }
    else
        str2.push_back(str[i]);
}

Answer 3

It isn't exactly 'mangling' the characters because of an escape sequence. The '\r' resets your cursor i.e. it is a carriage-return. Hence, your cursor goes to the beginning and whatever is typed now overwrites whatever is there on the line.

You can just erase any instance of \r in your string:

void Controller::write(const std::string& str) {
    std::string str2(str); //Make a copy of the string as you are getting a const reference
    char remove[] = "\r"; //Add any characters you wish to remove

    for (unsigned int i = 0; i < sizeof(chars); ++i) {
        str2.erase(std::remove(str2.begin(), str2.end(), chars[i]), str2.end());
    }

    std::cout << "Writing: [" << str2 << "] to board." << std::endl; 
    s.write(str);
}

NOTE: remove is a function in <algorithm>, so don't forget to #include <algorithm>.

EDIT: Code to make a copy added, thanks to jrok for pointing that one out :)