This was a very simple exercise, but since I said I would publish a solution, here it is.
Revised class definition (in Counter.h)
class Counter {
public:
Counter();
int count() const;
void increment();
void decrement(); // This line is the only change.
private:
int countM;
};
New function definition (in Counter.cpp)
void Counter::decrement()
{
countM--;
}
Revised definition of main (in exAprog.cpp)
int main()
{
Counter c;
cout << "initial value of c.count() is " << c.count() << endl;
c.increment();
c.increment();
cout << "after 2 increment calls, c.count() is " << c.count() << endl;
// The next three lines are new code to demonstrate the decrement
// function.
c.decrement();
c.decrement();
cout << "after 2 decrement calls, c.count() is " << c.count() << endl;
return 0;
}
void AList::remove(int pos)
{
assert(pos >= 0 && pos < length());
lengthM--;
for (int i = pos; i < lengthM; i++)
itemM[i] = itemM[i + 1];
}
Program output including tests of remove operation
expected contents: [empty list] actual contents : [empty list] expected contents: 11 22 33 44 55 actual contents : 11 22 33 44 55 expected contents: 500 400 300 200 100 actual contents : 500 400 300 200 100 expected contents: 101 501 401 301 201 actual contents : 101 501 401 301 201 expected contents: 501 401 301 201 actual contents : 501 401 301 201 expected contents: 501 401 301 actual contents : 501 401 301 expected contents: 501 301 actual contents : 501 301 No assertions failed. If actual contents always matched expected contents, all tests were passed.
Point Two:
Point Three:
void cplx_subtract(Cplx z1, Cplx z2, Cplx *presult)
{
presult->real = z1.real - z2.real;
presult->imag = z1.imag - z2.imag;
}
Cplx cplx_multiply(const Cplx *pz1, const Cplx *pz2)
{
Cplx result;
result.real = pz1->real * pz2->real - pz1->imag * pz2->imag;
result.imag = pz1->real * pz2->imag + pz1->imag * pz2->real;
return result;
}
void cplx_divide(const Cplx *pz1, const Cplx *pz2, Cplx *presult)
{
assert(pz2->real != 0 || pz2->imag != 0);
double a = pz1->real, b = pz1->imag;
double c = pz2->real, d = pz2->imag;
double c2_plus_d2 = c * c + d * d;
presult->real = (a * c + b * d) / c2_plus_d2;
presult->imag = (b * c - a * d) / c2_plus_d2;
}
(Note the use of local variables in cplx_divide--doing
this makes it much easier to check the code against the formula
in the instructions.)
Revised definition of main (in useCplx.cpp)
int main(void)
{
Cplx w, z; /* entered by user */
Cplx sum; /* sum of w and z */
Cplx diff; // w - z
Cplx product; // w * z
Cplx quotient; // w / z
cout << "This programs needs values for complex numbers w and z.\n";
cout << " Please enter the real part of w : ";
cin >> w.real;
cout << " Please enter the imaginary part of w: ";
cin >> w.imag;
cout << " Please enter the real part of z : ";
cin >> z.real;
cout << " Please enter the imaginary part of z: ";
cin >> z.imag;
cout << "\nw is (" << w.real << ") + j(" << w.imag << ").\n";
cout << "z is (" << z.real << ") + j(" << z.imag << ").\n";
sum = cplx_add(w, z);
cout << "\nsum is (" << sum.real << ") + j(" << sum.imag << ").\n";
cplx_subtract(w, z, &diff);
cout << "\nw - z is (" << diff.real << ") + j(" << diff.imag << ").\n";
product = cplx_multiply(&w, &z);
cout << "\nw * z is (" << product.real
<< ") + j(" << product.imag << ").\n";
cplx_divide(&w, &z, "ient);
cout << "\nw / z is (" << quotient.real
<< ") + j(" << quotient.imag << ").\n";
return 0;
}
