Is it possible to exit a loop on the change of an input state?

Question

I would like to exit a particular loop if the state of an input changes from LOW to HIGH. This is the current loop:

void brakeFade() {
pixels.clear();
pixels.setBrightness(255);
pixels.fill(16711680, 0, 0);
for(int i=255; i>=10; i-=1) {
 pixels.setBrightness(i);
 pixels.show();
 delay(5);
 }
for(int j=10; j<=255; j+=1) {
 pixels.setBrightness(j);
 pixels.show();
 delay(5);

} }

I need that loop to exit if

(digitalRead(brakeFeed) == LOW)

Changes to HIGH during the loop.

• jsotola: there is no reason to use two different named index variables, i and j, in the two for loops ... they can both be i .... increment can be done using i++ instead of i+=1 ... same with decrement

Answer 1

figured it out:

void brakeFade2() {
pixels.clear();
pixels.setBrightness(255);
pixels.fill(16711680, 0, 0);
for(int i=255; i>=10; i-=1) {
 if (digitalRead(brakeFeed) == LOW){
 pixels.setBrightness(i);
 pixels.show();
 delay(5);
 }
 else {
 break;
 }
}
for(int j=10; j<=255; j+=1) {
 if (digitalRead(brakeFeed) == LOW){
 pixels.setBrightness(j);
 pixels.show();
 delay(5);
 }
 else {
 break;
 }
 }

}

• jsotola: simpler way would be to add it to the completion test of the for loop ... for(int i=255; (i>=10) or (digitalRead(brakeFeed) == LOW); i--) {
• Duncan C: Wouldn't that be for(int i=255; (i>=10) && (digitalRead(brakeFeed) == LOW)? The OP wants the loop to continue as long as is >= 10, and the brakeFeed pin still reads as low. It should break if either of those stops being the case.