cpp/pointers/OneOrMany Source

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Property Value

Description
html markup
shown to student

Example showing that a pointer can point to a single (scalar) value or an array of values.

The person writing the function makes an assumption and the perons calling it should follow it.

Epilogue
html markup
shown when solved

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

Originally by Mark Redekopp (redekopp@usc.edu)

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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 <cstdlib>
using namespace std;

// ptr can point to one int or an array of ints
// It is up to the programmer to ensure that the
// assumptions of the function writer match
// what the user passes
void set_int(int* ptr, int size) {
\[

\show:
*ptr = 5; // same as ptr[0] = 5;

if(size > 1){
ptr[1] = 7; // only safe if
// an array of size > 1
}
]\
}

int main() {
int val1=0, vals_array[2] = {0,0};

// Pass a pointer to a single int
set_int(&val1, 1);

// Pass a pointer to an array
set_int(vals_array, 5);

// Print the results
cout << "val1 = " << val1 << endl;
cout << "vals_array: " << vals_array[0] << " " << vals_array[1] << 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"]

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

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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	Example showing that a pointer can point to a single (scalar) value or an array of values. The person writing the function makes an assumption and the perons calling it should follow it.
Epilogue html markup shown when solved	remove
Public permissions	remove
Remarks Comments, history, license, etc.	Originally by Mark Redekopp (redekopp@usc.edu) 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 <cstdlib> using namespace std; // ptr can point to one int or an array of ints // It is up to the programmer to ensure that the // assumptions of the function writer match // what the user passes void set_int(int* ptr, int size) { \[ \show: *ptr = 5; // same as ptr[0] = 5; if(size > 1){ ptr[1] = 7; // only safe if // an array of size > 1 } ]\ } int main() { int val1=0, vals_array[2] = {0,0}; // Pass a pointer to a single int set_int(&val1, 1); // Pass a pointer to an array set_int(vals_array, 5); // Print the results cout << "val1 = " << val1 << endl; cout << "vals_array: " << vals_array[0] << " " << vals_array[1] << 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

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