Question

Write a method that returns the result when the calling object is multiplied by a scalar value.
For example, the PolyTerm 2.4x^3 multiplied by -1.2 should return the PolyTerm object representing -2.88x^3.

Language: Java.
Method name be like: scalarMultiply(double)

Some Outputs:
Test 1: Coefficient =1, Exponent = 1
scalarMultiply(1.2).coefficient return 1.2;
scalarMultiply(1.2).exponent returns 1.

Test 2: Coefficient =2.4, Exponent = 3
scalarMultiply(-1.2).coefficient returns -2.88
scalarMultiply(-1.2).exponent return 3

Test 3: Coefficient =-1.5 Exponent = 0
scalarMultiply(0).coefficient returns 0
scalarMultiply(0).exponent returns 3

The actual question is:

PolyTerm t1, t2, t3, t4;

   @BeforeEach
   public void setUp() throws Exception {
       currentMethodName = null;
       t1 = new PolyTerm(1, 1); //x
       t2 = new PolyTerm(2.4, 3); //2.4x^3
       t3 = new PolyTerm(-1.5, 0); //-1.5
       t4 = new PolyTerm(3.6, -2); //3.6x^-2
   }

And it's respective JUnit test:

@Test @Order(6) @Graded(marks=8, description="scalarMultiply(double)")
   public void testScalarMultiply() {
       assertEquals(1.2, t1.scalarMultiply(1.2).coefficient, 0.001);
       assertEquals(1, t1.scalarMultiply(1.2).exponent);

       assertEquals(-2.88, t2.scalarMultiply(-1.2).coefficient, 0.001);
       assertEquals(3, t2.scalarMultiply(-1.2).exponent);

       assertEquals(0, t2.scalarMultiply(0).coefficient, 0.001);
       assertEquals(3, t2.scalarMultiply(0).exponent);

       assertEquals(-0.36, t4.scalarMultiply(-0.1).coefficient, 0.001);
       assertEquals(-2, t4.scalarMultiply(-0.1).exponent);

       currentMethodName = new Throwable().getStackTrace()[0].getMethodName();
   }

Answer 1

Code to paste

public PolyTerm scalarMultiply(double multiplier){
        return new Polyterm(coefficient * multiplier,exponent);

}

Driver program and screen shot