/* 24/07/2021
   mathematicsv2

   Subtraction 
    How integers can over run with subtraction

*/

int q;
int w;
int myAnswer;


void setup() {
  // Serial.begin(9600) starts serial communication. 9600bps bits per second = 1200 characters per second
  Serial.begin(9600);
  //Send script name
  Serial.println("mathematicsv2...");
  //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.println(q);
    //Simple addition
    Serial.println("Simple subtraction");
    for (w = 0; w < 10; w++) {
      myAnswer =  w - q;
      Serial.print(" w =");
      Serial.print(w);
      Serial.print(" myAnswer =");
      Serial.println(myAnswer);
    }
    //Example 2
    q = -10;
    Serial.println("Simple subtraction... - negative number double negative = positive");
    Serial.print("q = ");
    Serial.println(q);
    for (w = 0; w < 10; w++) {
      myAnswer =  w - q;
      Serial.print(" w =");
      Serial.print(w);
      Serial.print(" myAnswer =");
      Serial.println(myAnswer);
    }
    //Example 3
    q = -10;
    Serial.println("Simple subtraction...negative numbers");
    Serial.print("q = ");
    Serial.println(q);
    for (w = 0; w < 10; w++) {
      myAnswer =  q - w;
      Serial.print(" w =");
      Serial.print(w);
      Serial.print(" myAnswer =");
      Serial.println(myAnswer);
    }
    //example 4
    //change the value of q to 32760
    q = -32760;
    Serial.println("Simple subtraction...The problem of overflowing the variable type");
    Serial.print("q = ");
    Serial.println(q);
    for (w = 0; w < 10; w++) {
      myAnswer =  q - w;
      Serial.print(" w =");
      Serial.print(w);
      Serial.print(" myAnswer =");
      Serial.println(myAnswer);
    }
    
    //make q equal to 1 to make sure the if loop does not run again
    q = 1;
  }

}