1
h04
CS16 F18
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h04: Chapter 4: Predefined and programmer defined functions

ready? assigned due points
true Thu 10/18 12:30PM Wed 10/24 12:30PM

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 GRADESCOPE. There is NO MAKEUP for missed assignments;
in place of that, we drop the three lowest scores (if you have zeros, those are the three lowest scores.)

Please:

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

Read Chapter 4, sections 4.1 - 4.3. Please turn in the physical copy of your homework in person. Write in PEN or DARK PENCIL.

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?
    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. (10 pts) Write a Makefile to automate the compilation process for lab02. Your makefile should produce the executables: starC, starL, starT and starZ as specified in the writeup.
    6. (6 pts) The infinite series: s = 1 + (2/3) + (4/9) + (8/27) + .... is a geometric series that converges to a whole rational number (i.e. like 2 or 3 or 4). Below is an unfinished C++ program that will calculate s to the kth position (so, for example, if k = 1, then s = 1 + (2/3) = 1.666...). Fill in the missing code: 
    #include <iostream>
#include <cmath>
using namespace std;

int main(){
    double s(0.0);
    int k(0);
    cout << "Enter k: ";
    cin >> k;
    for (____________________________________________________) {

        s = ____________________________________________________; }

    cout << "Series converges to: " << s << endl;
    return 0;
}