cpp/cs102/practice13/stringDebug Source

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Description
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shown to student

Consider the following code, which has two incorrect (but nearly correct) methods. 
The code is supposed to implement two functions, one to "rotate" a string a certain amount of characters
to the left, and one to "rotate" a string a certain amount of characters to the right.
We recommend you try running the code to find the bugs. Use cout statements as necessary!
Correct the functions.

Epilogue
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shown when solved

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Remarks
Comments, history, license, etc.

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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 <string>

using namespace std;

string cycleLeft (unsigned int amount, string orig);
string cycleRight (unsigned int amount, string orig);

int main()
{
string temp, message;
cin >> message;
while(cin >> temp)
message += " " + temp;
cout << cycleLeft (12, message) << endl;
cout << cycleLeft(6, cycleRight(6, message)) << endl;
return 0;
}

string cycleLeft (unsigned int amount, string orig)
{
\[
REDACTED
\show:
string ans = orig;
char begin = ans[0];
for (int i = 0; i < amount; i++)
{
for (int j = 0; j < ans.size(); j++)
{
ans[j-1] = ans[j];
}
ans[ans.size()-1] = begin;
}
return ans;
]\
}

string cycleRight (unsigned int amount, string orig)
{
\[
REDACTED
\show:
string ans = orig;
for (int i = 0; i < amount; i++)
{
char end = ans[ans.size()];
for (int j = ans.size(); j >= 0; j--)
{
ans[j+1] = ans[j];
}
ans[0] = end;
}
return ans;
]\
}

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 [{}]

[
{"stdin":"Scramble this string!", "args":[]},
{"stdin":"Happy holidays!", "args":[]},
{"stdin":"Debugging is the most important skill!", "args":[]}
]
C++ test suite
See manual

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

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e.g. ["java.util.*"]

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

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

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

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Property	Value
Description html markup shown to student	<p>Consider the following code, which has two incorrect (but nearly correct) methods. </p> <p>The code is supposed to implement two functions, one to "rotate" a string a certain amount of characters to the left, and one to "rotate" a string a certain amount of characters to the right.</p> <p>We recommend you try running the code to find the bugs. Use cout statements as necessary! Correct the functions.</p>
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 <string> using namespace std; string cycleLeft (unsigned int amount, string orig); string cycleRight (unsigned int amount, string orig); int main() { string temp, message; cin >> message; while(cin >> temp) message += " " + temp; cout << cycleLeft (12, message) << endl; cout << cycleLeft(6, cycleRight(6, message)) << endl; return 0; } string cycleLeft (unsigned int amount, string orig) { \[ REDACTED \show: string ans = orig; char begin = ans[0]; for (int i = 0; i < amount; i++) { for (int j = 0; j < ans.size(); j++) { ans[j-1] = ans[j]; } ans[ans.size()-1] = begin; } return ans; ]\ } string cycleRight (unsigned int amount, string orig) { \[ REDACTED \show: string ans = orig; for (int i = 0; i < amount; i++) { char end = ans[ans.size()]; for (int j = ans.size(); j >= 0; j--) { ans[j+1] = ans[j]; } ans[0] = end; } return ans; ]\ }
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 `[{}]`	[ {"stdin":"Scramble this string!", "args":[]}, {"stdin":"Happy holidays!", "args":[]}, {"stdin":"Debugging is the most important skill!", "args":[]} ]
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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