This program from How To Test The SPI Module Of Arduino- (Part 32/49) gives a compile error (“empty character constant”) at this line:
for(i = 0; outByte !=’’; i ++)
The ‘’ are really two separate ', not a single".
What do I overlook?
*#include <SPI.h> // including the SPI library
char outByte  = “ENGINEERS GARAGE”; // string to be send and received via SPI port
int led = 6; // variable which holds the pin number at which the LED is attached
char inByte; // variable which stores the value of the byte received from SPI bus
int i = 0;
pinMode(led, OUTPUT); // setting the LED pin as output
Serial.begin(9600); // initializing the serial port at 9600 baud rate
SPI.begin(); // initialize the SPI port as master
for(i = 0; outByte [i] !=’’; i ++) // send and receive the bytes of the string
inByte = SPI.transfer(outByte [i]);