Get Max and Min Values of an Array in Arduino

In order to get the max/ min values of an array in Arduino, we can run a simple for loop. Two implementations are shown below. One uses the max() and min() functions of Arduino, and the other uses the > and < operators.

The max and min functions have the following syntax: max(a,b) and min(a,b), and they return the max and min values out of a and b respectively.

Implementation 1 − Using > and < operators

void setup() {
   // put your setup code here, to run once:
   Serial.begin(9600);
   Serial.println();
   int myArray[6] = {1, 5, -6, 4, -2, 7};

   int maxVal = myArray[0];
   int minVal = myArray[0];
   Serial.print("Size of myArray is: "); Serial.println(sizeof(myArray));

   for (int i = 0; i < (sizeof(myArray) / sizeof(myArray[0])); i++) {
      if (myArray[i] > maxVal) {
         maxVal = myArray[i];
      }
      if (myArray[i] < minVal) {
         minVal = myArray[i];
      }
   }
   Serial.print("The maximum value of the array is: "); Serial.println(maxVal);
   Serial.print("The minimum value of the array is: "); Serial.println(minVal);
}

void loop() {
   // put your main code here, to run repeatedly:
}

Implementation 2 − Using max and min

void setup() {
   // put your setup code here, to run once:
   Serial.begin(9600);
   Serial.println();
   int myArray[6] = {1, 5, -6, 4, -2, 7};

   int maxVal = myArray[0];
   int minVal = myArray[0];
   Serial.print("Size of myArray is: "); Serial.println(sizeof(myArray));

   for (int i = 0; i < (sizeof(myArray) / sizeof(myArray[0])); i++) {
      maxVal = max(myArray[i],maxVal);
      minVal = min(myArray[i],minVal);
   }

   Serial.print("The maximum value of the array is: ");
Serial.println(maxVal);
   Serial.print("The minimum value of the array is: ");
Serial.println(minVal);
}

void loop() {
   // put your main code here, to run repeatedly:
}

Output

The Serial Monitor output in both the cases is −

As you can see, the sizeof() function is returning the total number of bytes and not the number of elements in the array (I’m using a board which stores int in 4 bytes). Therefore, within the for loop, the condition has been kept as −

i < (sizeof(myArray) / sizeof(myArray[0]))