Adding a feature

• Subtraction

• Write the test:

      public void testSubtract() {
   
          Complex z1 = new Complex(1, 1);
          Complex z2 = new Complex(1, 1);
          Complex z3 = z1.subtract(z2);
          assertEquals(0, z3.getRealPart(), tolerance);
          assertEquals(0, z3.getImaginaryPart(), tolerance);
    
      }    

• Implement the feature:

      public Complex subtract(Complex z) {
          // ???? Auto-generated method stub
          return null;
      }

• Debug until the test passes:

      public Complex subtract(Complex z) {
          return new Complex(this.real - z.real, this.imaginary - z.imaginary);
      }