sending data through serial port in c++ - c++

Question

I have copied this code to write through the serial port in c++. It works properly, but what I need now is to know how to convert a string into an array of bytes, because I want to write several strings to communicate with an arduino. I paste the code here:
#include <windows.h>
#include <stdio.h>
int main()
{
// Define the five bytes to send ("hello")
char bytes_to_send[5];
bytes_to_send[0] = 104;
bytes_to_send[1] = 101;
bytes_to_send[2] = 108;
bytes_to_send[3] = 108;
bytes_to_send[4] = 111;
// Declare variables and structures
HANDLE hSerial;
DCB dcbSerialParams = {0};
COMMTIMEOUTS timeouts = {0};
// Open the highest available serial port number
fprintf(stderr, "Opening serial port...");
hSerial = CreateFile(
"\\\\.\\COM1", GENERIC_READ|GENERIC_WRITE, 0, NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL );
if (hSerial == INVALID_HANDLE_VALUE)
{
fprintf(stderr, "Error\n");
return 1;
}
else fprintf(stderr, "OK\n");
// Set device parameters (38400 baud, 1 start bit,
// 1 stop bit, no parity)
dcbSerialParams.DCBlength = sizeof(dcbSerialParams);
if (GetCommState(hSerial, &dcbSerialParams) == 0)
{
fprintf(stderr, "Error getting device state\n");
CloseHandle(hSerial);
return 1;
}
dcbSerialParams.BaudRate = CBR_38400;
dcbSerialParams.ByteSize = 8;
dcbSerialParams.StopBits = ONESTOPBIT;
dcbSerialParams.Parity = NOPARITY;
if(SetCommState(hSerial, &dcbSerialParams) == 0)
{
fprintf(stderr, "Error setting device parameters\n");
CloseHandle(hSerial);
return 1;
}
// Set COM port timeout settings
timeouts.ReadIntervalTimeout = 50;
timeouts.ReadTotalTimeoutConstant = 50;
timeouts.ReadTotalTimeoutMultiplier = 10;
timeouts.WriteTotalTimeoutConstant = 50;
timeouts.WriteTotalTimeoutMultiplier = 10;
if(SetCommTimeouts(hSerial, &timeouts) == 0)
{
fprintf(stderr, "Error setting timeouts\n");
CloseHandle(hSerial);
return 1;
}
// Send specified text (remaining command line arguments)
DWORD bytes_written, total_bytes_written = 0;
fprintf(stderr, "Sending bytes...");
if(!WriteFile(hSerial, bytes_to_send, 5, &bytes_written, NULL))
{
fprintf(stderr, "Error\n");
CloseHandle(hSerial);
return 1;
}
fprintf(stderr, "%d bytes written\n", bytes_written);
// Close serial port
fprintf(stderr, "Closing serial port...");
if (CloseHandle(hSerial) == 0)
{
fprintf(stderr, "Error\n");
return 1;
}
fprintf(stderr, "OK\n");
// exit normally
return 0;
}
Here is the part I want to change:
// Define the five bytes to send ("hello")
char bytes_to_send[5];
bytes_to_send[0] = 104;
bytes_to_send[1] = 101;
bytes_to_send[2] = 108;
bytes_to_send[3] = 108;
bytes_to_send[4] = 111;
I want to use my own strings and a method to transform them into bytes, so that I can send them through the serial port.

Answer 1

A string already is an array of bytes.
char bytes_to_send[] = "hello";