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Question: i need help fixing some code written as an answer...
Question details
I need help fixing some code written as an answer to a question on here. I have updated the description with input and the corresponding expected output.
I removed the link because apparently that makes the problem unclear. I am including the rules for determining if something is a token ('cause that's what I provided the link for).
Determining if something is a token:
1. Whitespace (space, tab, etc) ends a token and is skipped
unless it is in quotes (see below). You will find the function int
isspace(char) useful for detecting whitespace characters.
2. Some characters are considered special tokens: | ; < >
&. When one of these characters is encountered, the token being
built is completed and a new token consisting of the character is
created.
3. The character \ is a special character, i.e. an escape
character. The next character will be part (or the start) of a
token.
4. Items between single or double quotes are treated as parts of
the current token.
5. Characters that do not meet the above rules are added on to the
current token being built.
Problems with the current code:
The output of we\'ll do some "crazy \"air quotes\"" should not
include the first and last ", i.e. crazy "air quotes" is the token
and not "crazy "air quotes"". Another example would be an input of
I" like Linux", which would give one token of I like Linux as the
output (it's recognizing the spaces because the spaces are between
quotes).
Correct input/output examples for above:
Input: we\'ll do some "crazy \"air quotes\""
Output: [{we'll},{do},{some},{crazy "air quotes"}]
Input: I" like Linux"
Output: [{I like Linux}]
In cases where it shouldn't, it's treating spaces like tokens. For example,the output of ls | sort >sorted_files.txt should be five tokens, none of which should be spaces.
Correct input/output examples for above:
Input: ls | sort >sorted_files.txt
Output: [{ls},{|},{sort},{>},{sorted_files.txt}]
Please change the code to correct the above issues.
#include
#include
#include
using namespace std;
// function to determine if a token
vector is_token(const string& s)
{
vector tokens;
//Get the length of input string
int nLen = s.length();
//variable to hold each token parsed
string token;
for(int i=0;i {
//if the character encountered is
space , token construction is completed.
if (isspace(s[i]))
{
//Remove the ''
if any
size_t spos =
token.find("\", 0);
if (spos !=
string::npos)
{
token.replace(spos, 1, "");
}
//Add the new
token to vector
tokens.push_back(token);
token.clear();
}
//if charater is encountered is one
of |,;,<,>,& , treat them as 1 token and add it to the
tokens vector
else if((s[i] == '|') || (s[i] ==
';') || (s[i] == '<') || (s[i] == '>') || (s[i] ==
'&'))
{
tokens.push_back(token);
token.clear();
string
temp;
temp.push_back(s[i]);
tokens.push_back(temp);
}
else //normal character other than
above, continue constructing the token
{
token.push_back(s[i]);
}
//if '' is encountered ,add the
next character to the current token
if (s[i] == '\')
{
i++;
token.push_back(s[i]);
}
}
//last token, remove '' if any and add the token to
vector
size_t spos = token.find("\", 0);
if (spos != string::npos)
{
token.replace(spos, 1, "");
}
tokens.push_back(token);
//return the tokens vector
return tokens;
}
int main() {
// loop to get input is accepted until the user hits
CTRL+d
while (true)
{
string str;
cout << "(Ctrl+D) to exit
>";
getline(cin, str);
//if user pressed Ctrl+D exit
out of loop
if (str.compare("x4") == 0)
break;
//vector to store the strings or
characters returned by is_token() function
vector tokens;
tokens = is_token(str);
cout << " Output tokens:
";
for (int i = 0; i <
tokens.size(); i++)
{
cout <<
tokens[i] << " ";
}
cout << endl;
}
}
Solution by an expert tutor
