cpp/cs104/classes/constructor

Viewing cpp/cs104/classes/constructor_init by redekopp@usc.edu. You have unsaved changes. Log in above to create, edit, preview and publish Websheets.

Property Value

Description
html markup
shown to student

Consider the initialization of <tt>ObjB::a</tt> (i.e. we want to initialize <tt>val</tt> that is a member of <tt>a</tt>. Our goal is to initialize <tt>val</tt> with the value of <tt>w</tt> from
the <tt>ObjB</tt> constructor.
<p>
How can we do this? <strong>Note:</strong> <tt>ObjA</tt> does not have any public <tt>set</tt>/<tt>mutator</tt> functions...only the constructor allows us to set <tt>value</tt>

Epilogue
html markup
shown when solved

remove
Public permissions remove
Remarks
Comments, history, license, etc.

remove
Engine
Choices
json list of string, bool pairs
e.g. [["good", true], ["bad", false]]

Correct answer
Template / Reference solution

Template / Reference solution

#include <iostream>
#include <algorithm>
using namespace std;

class ObjA
{
public:
ObjA(int v) {
val = v;
}
int get() const { return val; }
private:
int val;
};

class ObjB
{
public:
ObjB(int w)
\[
REDACTED
\show:
{
// what's wrong with this attempt?
ObjA a(w);
}
]\
int get() const { return a.get(); }

private:
ObjA a;
};

int main()
{
ObjB b(10);
cout << "B's output: " << b.get() << endl;
return 0;
}

Java test suite
See manual

C++ test suite
json list of stdin/args tests
e.g. [{"stdin":"hi", "args":["4", "5"]}, {"stdin":"noargs"}]
to just run once with no input use [{}]

[{}]
C++ test suite
See manual

Forbidden substrings
json list of strings
e.g. ["for","while"]

remove
Solution visibility remove
Java imports
json list of importables
e.g. ["java.util.*"]

remove
Override Java classname
else defaults to
websheet name
remove
Dependent on other websheets?
json list of websheet names in this folder
e.g. ["DataStructure"]

remove
Is example?
i.e., just a demo
remove
Add compiler flag(s)
json list of flags
e.g. ["-Wno-unused-variable"]

remove
Remove default compiler flag(s)
json list of flags
see default_cppflags
e.g. ["-Wno-write-strings"]

remove

Property	Value
Description html markup shown to student	Consider the initialization of <tt>ObjB::a</tt> (i.e. we want to initialize <tt>val</tt> that is a member of <tt>a</tt>. Our goal is to initialize <tt>val</tt> with the value of <tt>w</tt> from the <tt>ObjB</tt> constructor. <p> How can we do this? <strong>Note:</strong> <tt>ObjA</tt> does not have any public <tt>set</tt>/<tt>mutator</tt> functions...only the constructor allows us to set <tt>value</tt>
Epilogue html markup shown when solved	remove
Public permissions	remove
Remarks Comments, history, license, etc.	remove
Engine
Choices json list of string, bool pairs e.g. `[["good", true], ["bad", false]]`
Correct answer
Template / Reference solution
Template / Reference solution	#include <iostream> #include <algorithm> using namespace std; class ObjA { public: ObjA(int v) { val = v; } int get() const { return val; } private: int val; }; class ObjB { public: ObjB(int w) \[ REDACTED \show: { // what's wrong with this attempt? ObjA a(w); } ]\ int get() const { return a.get(); } private: ObjA a; }; int main() { ObjB b(10); cout << "B's output: " << b.get() << endl; return 0; }
Java test suite See manual
C++ test suite json list of stdin/args tests e.g. `[{"stdin":"hi", "args":["4", "5"]}, {"stdin":"noargs"}]` to just run once with no input use `[{}]`	[{}]
C++ test suite See manual
Forbidden substrings json list of strings e.g. `["for","while"]`	remove
Solution visibility	remove
Java imports json list of importables e.g. `["java.util.*"]`	remove
Override Java classname else defaults to websheet name	remove
Dependent on other websheets? json list of websheet names in this folder e.g. `["DataStructure"]`	remove
Is example? i.e., just a demo	remove
Add compiler flag(s) json list of flags e.g. `["-Wno-unused-variable"]`	remove
Remove default compiler flag(s) json list of flags see default_cppflags e.g. `["-Wno-write-strings"]`	remove

Optional properties:

Note: problems are open-source by default (see 'Public permissions'). Assumed license for open problems is Creative Commons 4.0 Attribution-ShareAlike unless specified in 'Remarks'.