6.1

    1. f1.num = f1.num * 2;
    2. int temp = f2.num;
f2.num = f2.den;
f2.den = temp;
    3. f1.num = f1.num * f2.num;
f1.den = f1.den * f2.den
    4. f2.num = f1.num * f2.den + f2.num * f1.den;
f2.den = f1.den * f2.den;
    5. if (f1.num < 0)
   f1.num = f1.num * -1;
if (f1.den < 0)
   f1.den = f1.den * -1;
  2.   
    void setup()
{
   // Part (a)
   Circle c1 = new Circle();
   Circle c2 = new Circle();
   c1.x = 1;
   c1.y = 2;
   c1.r = 4;
   c2.x = -2;
   c2.y = 0;
   c2.r = 2;
   // Part (b)
   float distance = sqrt(pow(c1.x,2) + pow(c1.y,2));
   println(distance);
   // Part (c)
   float centreSeparation = sqrt(pow(c1.x - c2.x,2) + pow(c1.y - c2.y,2));
   println(centreSeparation);
   // Part (d)
   float minDistance = centreSeparation - c1.r - c2.r;
   if (minDistance < 0)
      minDistance = 0; // circles are overlapping
   println(minDistance);
} 
    1. class Complex
{
   float a;
   float b;
} 
    2. Complex z1 = new Complex();
Complex z2 = new Complex();
z1.a = 2;
z1.b = 3;
z2.a = 5;
z2.b = -4; 
    3. z1.a = z1.a + z2.a;
z1.b = z1.b + z2.b;