int A4 conflict declaration

Forum 2005-2010 (read only) Software Syntax & Programs
1

Hi guys, am doing a very simple program to produce the C major scale, however when creating an interger variable "A4" to store the frequency 2272Hz, i get "conflicting declaration 'int A4'. I can fix the problem by just putting it in lower case.

However, am interested in the reason why that is happening

The code is bellow

int C4 = 3830; 
int D4 = 3400; 
int E4 = 3038;
int F4 = 2864; 
int G4 = 2550; 
int A4 = 2272; 
int B4 = 2028; 
int C5 = 1912; 

int duration = 500;
int pinTone = 7;

void setup() {
  pinMode (pinTone, OUTPUT);
}

void tone(int period, int length) {
  long M = millis() + length;
  while(millis() < M) {
    digitalWrite(pinTone, HIGH);
    delayMicroseconds(period/2);
    digitalWrite(pinTone, LOW);
    delayMicroseconds(period/2);
  }
} 

void loop() {  
  tone(C4, duration);
  tone(D4, duration);
  tone(E4, duration);
  tone(F4, duration);
  tone(G4, duration);
  tone(A4, duration);
  tone(B4, duration);
  tone(C5, duration);
}

Thanks a lot!
Carlos

2

Probably because there's another A4 in one of the headers Arduino uses.
I'm guessing Tone.h.
Or maybe "papersizes.h"

3

The analog pins got aliases assigned in 0019 or 0020. The names A1 - A5 are now reserved keywords.

4

Thanks a lot PaulS, that was very much what i was looking for!