Add all the A tasks

Task/Arithmetic-Complex/Java/arithmetic-complex.java

@@ -0,0 +1,44 @@
+public class Complex{
+   public final double real;
+   public final double imag;
+
+   public Complex(){this(0,0)}//default values to 0...force of habit
+   public Complex(double r, double i){real = r; imag = i;}
+
+   public Complex add(Complex b){
+      return new Complex(this.real + b.real, this.imag + b.imag);
+   }
+
+   public Complex mult(Complex b){
+      //FOIL of (a+bi)(c+di) with i*i = -1
+      return new Complex(this.real * b.real - this.imag * b.imag, this.real * b.imag + this.imag * b.real);
+   }
+
+   public Complex inv(){
+      //1/(a+bi) * (a-bi)/(a-bi) = 1/(a+bi) but it's more workable
+      double denom = real * real + imag * imag;
+      return new Complex(real/denom,-imag/denom);
+   }
+
+   public Complex neg(){
+      return new Complex(-real, -imag);
+   }
+
+   public Complex conj(){
+      return new Complex(real, -imag);
+   }
+
+   public String toString(){ //override Object's toString
+      return real + " + " + imag + " * i";
+   }
+
+   public static void main(String[] args){
+      Complex a = new Complex(Math.PI, -5) //just some numbers
+      Complex b = new Complex(-1, 2.5);
+      System.out.println(a.neg());
+      System.out.println(a.add(b));
+      System.out.println(a.inv());
+      System.out.println(a.mult(b));
+      System.out.println(a.conj());
+   }
+}