// I heavily modified the original code, because Arduino provides functions
// which parse the serial input for you, thus not requiring the manual checking
// for newline characters, casting data types, dealing with things 1 byte at a time, etc.

void setup() 
{
  Serial.begin(9600);
  Serial.println("Enter the number of Multiplications (up to 25), and then the pairs of numbers to be multiplied (in a list separated by spaces or commas");
  Serial.setTimeout(5000); // max time allowed between serial inputs
}

void loop()
 {
  int numOfMults = 0;                             // number of pairs to multiply
  float *numArray;                                // pointer to beginning of array memory block
  numArray = (float *)malloc(sizeof(float)*50);   // dynamically allocate an array that can hold up to 50 floats 

  numOfMults = Serial.parseInt(); // take in the number of multiplications from user

  Serial.println(numOfMults);

  // take in the specified amount of numbers (2 times the num of multiplications) in format: 1,2,3...
  // then convert that into an array of floats, where every 2 indices
  // is a pair of numbers to multiply
  for (int i = 0; i < (2*numOfMults) ;i++)
    {
      numArray[i] = Serial.parseFloat();
      Serial.println(numArray[i]);
    } 
      multNums(numOfMults,numArray);  // call function to get the product of all the numbers 

      delay(5000);                    // wait 5 seconds before starting the loop again
 }
 
void multNums(int numofNums,float nums[])
{
  float *productArray;                                 // pointer to beginning of the product array memory block
  productArray = (float *)malloc(sizeof(float)*25);    // dynamically allocate an array that can hold up to 25 floats (for the products)

  // multiply all the number pairs in the array, store the product in another
  for(int i=0;i<numofNums;i+2)
  {
      productArray[i/2] = nums[i]*nums[i+1];         // multiply current number pair, store in the product array one index at a time 
  }
  // print the products
  for(int i=0; i < sizeof(productArray) ;i++)
  {
    Serial.println(productArray[i]);
  }
}