Can't understand how the program is working

Question

How does the Serial monitor display '12594' when we write Serial.print('12');?I have used single quotes intentionally.

[code]

void setup()

{

Serial.begin(9600);

Serial.print('12');

}

void loop()

{

}

[/code]

Robert Peter Oakes · Accepted Answer

when you output '12' your outputting 2 characters, a '1' and then a '2', this results in hex 31 or dec 49 being transmitted followed by a 32hex / 50dec, if you concatinate the two into a single integer then you get 12594, sending the 10 works out to be 12592, 11=12593

the print statement is interpreting this as an integer (16bits) instead of two 8 bit characters because in C the character literal is defined as an int and your providing just the right number of 8 bit characters to make an int

if you want to send the string literal "12" then you need the double quotes, this will also terminate the string correctly in the code so the actual memory used in this case would be 3 bytes '1','2','/0'

hope that helps

http://www.asciitable.com/

gadget.iom · Answer

Single quotes are typically used to declare character constants (that means only on character is permitted within the quotes). The compiler should give you warning if you try to include more than one character. sketch_dec17a.ino:4:14: warning: multi-character character constant [-Wmultichar] In practice, what you are seeing is down to either of the following: 
 The value of 'ab' is likely to be either 'a' * 256 + 'b' 
 or 'b' * 256 + 'a'. It will vary from one compiler to another. 
 In his case (where ASCII 1=49 and ASCII 2=50 you are likely seeing: (49*256)+50 = 12594

Can't understand how the program is working

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