1
h04
CS16 s20
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h04: Chapter 4: Predefined and programmer defined functions

ready? assigned due points
true Fri 04/17 11:00AM Fri 04/24 11:59PM

You may collaborate on this homework with AT MOST one person, an optional "homework buddy".

MAY ONLY BE TURNED IN IN THE LECTURE/LAB LISTED ABOVE AS THE DUE DATE,
OR IF APPLICABLE, SUBMITTED ON GAUCHOSPACE. There is NO MAKEUP for missed assignments;

Please:

  • No Staples.
  • No Paperclips.
  • No folded down corners.

Read Chapter 4, sections 4.1 - 4.3. Also read enough of chapter 3.4 to answer question 1. Please note that while the book does not cover number representation, it is an important concept for this class. Questions 3 to are meant to give you more practice with number representation. You don’t need to turn this homework in. To earn credit for this homework, complete the corresponding quiz on gauchospace AFTER you have completed the pen and pencil version of the homework. The quiz will be available at least one day before the due date indicated on the homework.

PLEASE MARK YOUR HOMEWORK CLEARLY, REGARDLESS OF IF YOU WRITE IT OUT IN INK OR PENCIL!

    1. (2 pts) What is a flag in a program and of what use is it? (The definition is in chapter 3.4.)
    2. (2 pts) What is type casting and how is it performed in C++?
    3.(5 pts) Which of these uses of type casting will NOT ensure that f is 1.5? Answer should be (ex1), (ex2), (ex3), or (ex4) (or a combination of those). 
    int a(1), b(2), c(2), d(2), e(2);
double f;

f = (a + b)*c / static_cast<double>(d + e); // (ex1)
f = static_cast<double>(a + b)*c / (d + e); // (ex2)
f = (a + b)*static_cast<double>(c) / (d + e); // (ex3)
f = static_cast<double>((a + b)*(c) / (d + e)); // (ex4)
    4.(3 pts) We talked about three concepts that are very important to keep straight, and not confuse: (a) function declaration, (b) function definition, and (c) function call. Here is a short C++ program, with line numbers. Please indicate after the program which line number (or range of line numbers, e.g. 3-5 or 7-14) contains the function prototype, function definition, and function call for the isDivisibleBy function. 
    1  #include <iostream>
2  using namespace std;
3
4  bool isDivisibleBy(int a, int b);
5
6  int main() {
7     cout << "result for (15,5) is " << isDivisibleBy(5,15) << endl;
8     cout << "result for (15,5) is " << isDivisibleBy(5,15) << endl;
9     return 0;
10  }
11
12  bool isDivisibleBy(int a, int b) {
13    return ( a % b == 0 );
14  }
    5.(8 pts) Write a function declaration and a function definition for a function that takes one argument of type int and one argument of type double, and that returns a value of type double that is the average of the two arguments.