/* 24/07/2021
   mathematicsv3

   Multiplication
   How integers can over run with multiplication and give very unexpected results

*/

int q;
int w;
int myAnswer;
long myLongAnswer;

void setup() {
  // Serial.begin(9600) starts serial communication. 9600bps bits per second = 1200 characters per second
  Serial.begin(9600);
  //Send script name
  Serial.println("mathematicsv3...");
  //this will print a blank line
  Serial.println(" ");

}

void loop() {
  if (q < 1) {
    //Example 1
    //make q = 1 so the if statement will fail next time round
    q = 1;
    Serial.print("q = ");
    Serial.print(q);
    //Simple multiplication
    Serial.println("Simple multiplication");
    for (w = 0; w < 10; w++) {
      // the symbol for multiplication is *
      myAnswer =  w * q;
      Serial.print(" w =");
      Serial.print(w);
      Serial.print(" myAnswer =");
      Serial.println(myAnswer);
    }

    //change the value of q to 32760
    q = 32760;
    //the answer can be positive or negative depending on the amount of over run.
    Serial.println("Simple multiplication...The problem of overflowing the variable type");
    Serial.print("q = ");
    Serial.print(q);
    for (w = 0; w < 10; w++) {
      myAnswer =  w * q;
      Serial.print(" w =");
      Serial.print(w);
      Serial.print(" myAnswer =");
      Serial.println(myAnswer);
    }
    //Example 3
    //change the value of q to 32760
    q = 32760;
    Serial.println("Simple multiplication... 2 integers converted to a long");
    Serial.print("q = ");
    Serial.print(q);
    for (w = 0; w < 10; w++) {
      myLongAnswer =  long(w) * long(q);
      Serial.print(" w =");
      Serial.print(w);
      Serial.print(" myLongAnswer =");
      Serial.println(myLongAnswer);
    }



  }

}