string data, what am I missing?

Projects Programming
1

So I'm trying to make a variable string that will be lcd.print():ed , the print function is running all the time in the loop and the string is changed depending on the case called, I got it working just fine using String but "everyone" is going nuts about using String instead of string, so I decided to "fix it", also to point out the name for string in the Reference is String and that should be fixed if it is actually with a lower case.

In the beginning I have defined

char lineOne[16];

In the main loop I print it

lcd.clear();
lcd.home();
lcd.print(lineOne);
lcd.setCursor(0,1);
lcd.print(lineTwo);

and in the case I change it

lineOne = "Measuring";

But in the verification I get

In function 'void loop()':

error: incompatible types in assignment of 'const char [10]' to 'char [16]'

lineOne = "Measuring";

The string length won't be larger than 16 characters for sure, since I'm using an 8x2 LCD.

So what am I doing wrong, how can I define the max string length?

I don't want code that changes the max length dynamically, I want it constant, I don't really care for it using less memory, I have seen the posts that add a bunch of code the make the length dynamic bla bla bla, I want to keep it simple.

Thanks
Oscar

2

Use strcpy

3 
char lineOne[16];

lineOne = "Measuring";

"strings" are annoying to deal with, because you can't use "normal" C operators like "=" or "+" with them; they are essentially (exactly) arrays, and you can't say lineOne = "Measuring"; any more than you could say "myarray = {1,2,3,4,5};"
Instead, you have to use functions. "strcpy" is efficient to use for simple cases, "sprintf" is something you can look at to do more complicated formatting.

strcpy(lineOne, "Measuring");
//or (better):
strcpy_P(lineOne, PSTR("Measuring"));
4

Changed it to

strcpy (lineOne,"Measuring");

Works exactly as I wanted.

Thank you very much AWOL and westfw!

Oscar

5

ckambiselis:
also to point out the name for string in the Reference is String and that should be fixed if it is actually with a lower case.

Thanks for reporting this! That change was made recently in error. I have submitted a pull request to fix it: