Exercise Answers

Exercise 1

Exercise 1 (written):

  1. Write a function which returns twice the input
  2. Write a function which return the negative of its input
f(x)=2∗x f(x) = 2 * x
f(x)=−x f(x) = -x

Exercise 2

Exercise 2: What value is output (returned) by PlusOne(-1)?

0

Exercise 3:

  1. Write a C function which takes a input a a single integer parameter returns twice the value.
int Twice(int x)
{
    return 2 * x;
}
  1. Write a C function which returns takes a single integer input parameter returns twice the value of it.
int Negative(int x)
{
    return -x;
}
  1. Write a C function which takes two integer parameters and returns the first minus the second
int Subtract(int a, int b)
{
    return a - b;
}

Exercise 4:

Exercise 4: What is the value returned by AddThreeTimes_v2(11)?

11 + 10 + 10 + 10 = 41

Exercise 5:

Exercise 5: Write a function that takes a double named radius as input and returns a double which is the area of a circle with that radius. (hint: you can approximate π\pi as 3.1412)

double CircleArea(double radius)
{
    double pi = 3.1412;
    return pi * radius * radius;
}

Of course its OK if oyu named your function differently, or maybe didn't have the separate line defining a variable for pi.