Starting Kit, project #7 - Keyboard Instrument

Projects Programming
1

The code as written on the project book is as follows:

int buttons[6]; // sets up a 6 element array
int buttons[0] = 2; // assigns 2 to the first element of the array

// sets up a 4 element array and intializes it. Starts out with
// frequencies for C (262 Hz), D (294 Hz), E (330 Hz) and F (349 Hz).
// Because it is declared before setup(), it is aglobal variable array
int notes[] = {262, 294, 330, 349};

void setup()
{
Serial.begin(9600); // starts serial comm with computer
}

void loop()
{
int keyVal = analogRead(A0); // reads pin A0 and stores value in keyVal
Serial.println(keyVal);

// using an If Else loop to assign each a value a different tone
if(keyVal == 1023)
{
tone(8, notes[0]);
}

else
if(keyVal >= 990 && KeyVal <= 1010)
{
tone(8, notes[1]);
}

else
if(keyVal >= 505 && keyVal <=515)
{
tone(8,notes[2]);
}

else
if(keyVal >= 5 && keyVal <=10)
{
tone(8,notes[3]);
}

else
{
noTone(8); // stops playing notes when no button is pressed
}
}

As written, it gives me the following two errors:

Arduino: 1.8.8 (Windows Store 1.8.19.0) (Windows 10), Board: "Arduino/Genuino Uno"
sketch_07A_feb18_Keyboard_Instrument:2:14: error: conflicting declaration 'int buttons [0]'
int buttons[0] = 2; // assigns 2 to the first element of the array
C:\Users\luisc\Downloads\sketch_07A_feb18_Keyboard_Instrument\sketch_07A_feb18_Keyboard_Instrument.ino:1:5: note: previous declaration as 'int buttons [6]'
int buttons[6]; // sets up a 6 element array

C:\Users\luisc\Downloads\sketch_07A_feb18_Keyboard_Instrument\sketch_07A_feb18_Keyboard_Instrument.ino: In function 'void loop()':
sketch_07A_feb18_Keyboard_Instrument:26:23: error: 'KeyVal' was not declared in this scope
if(keyVal >= 990 && KeyVal <= 1010)
exit status 1
conflicting declaration 'int buttons [0]'

I´m able to clear the first error by changing the first and second lines to read:

int buttons[] = {2, 0, 0, 0, 0, 0}; // sets up and defines a 6 element array
// int buttons[0] = 2; // assigns 2 to the first element of the array

but I´ve been unable to clear the second error:
'KeyVal' was not declared in this scope
if(keyVal >= 990 && KeyVal <= 1010)

Suggestion are welcome!!!

2

Please look at the way the code in your post appears.
Now read read this before posting a programming question
Now post it with code tags around it to avoid any of it being interpreted as HTML commands

3

Fix the first error properly by substituting

buttons[0] = 2;  // assigns 2 to the first element of the array

for

int buttons[0] = 2;  // assigns 2 to the first element of the array

Fix the second error by reading

  if(keyVal >= 990 && KeyVal <= 1010)

carefully and decide whether the variable is named KeyVal or keyVal

4

Thank you very much UKHeliBob. Thank you for the quick response. That solves the second error but not the first. I appreciate your time and effort. The code, as in the project book is as follows:

int buttons[6]; // sets up and defines a 6 element array
int buttons[0] = 2; // assigns 2 to the first element of the array

it wont compile, it gives the following error:

conflicting declaration 'int buttons [0]',

I went around it by rewriting the first line and rem the second to:

int buttons[] = {2, 0, 0, 0, 0, 0}; // sets up and initializes a 6 element array
// int buttons[0] = 2; // assigns 2 to the first element of the array

I´m still curious as why it does not compile as published in the project book. Again thanks for yor time

5 
int buttons[6];  // sets up a 6 element array
int buttons[0] = 2;  // assigns 2 to the first element of the array

This is not part of the sketch, but a broken example of using arrays.
Delete these lines.

Note: you can find the book examples under File > Examples > 10.StarterKit_BasicKit.

6

The code as written on the project book is as follows:

What project book? The example sketch supplied with the Arduino does NOT look like what you (mis)typed.

If the book is that bad, set it on fire.

7

I stand corrected, thank you @oqibidipo@

Thank you all. Case closed!!!