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getline(cin,s);
istringstream iss(s);
do
{
string sub;
iss>>sub;
q.insert(sub);
}while(iss);
I used this technique when question wanted me to split on the basis of space so can anyone explain me how to split when there's a particular delimiter like ';' or ':'.
Someone told me about strtok function but i am not able to get it's usage so it would be nice if someone could help.
First, don't use strtok. Ever.
There's not really a function for this in the standard library.
I use something like:
std::vector<std::string>
split( std::string const& original, char separator )
{
std::vector<std::string> results;
std::string::const_iterator start = original.begin();
std::string::const_iterator end = original.end();
std::string::const_iterator next = std::find( start, end, separator );
while ( next != end ) {
results.push_back( std::string( start, next ) );
start = next + 1;
next = std::find( start, end, separator );
}
results.push_back( std::string( start, next ) );
return results;
}
I believe Boost has a number of such functions. (I implemented
most of mine long before there was Boost.)
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I want to print out the number entered by the user as a whole and want to ignore the spaces.
Like this:
int aValue;
cin >> aValue;
Here, suppose the user enters 49 506, I want to print it as 49506.
First you need to get a string from a user with spaces, note you need to use std::getline() for that, as operator>> would not accept spaces:
std::string str;
std::getline( cin, str );
then you use std::remove_if() together with std::isspace() to remove spaces from your string:
auto it = std::remove_if( str.begin(), str.end(), []( unsigned char c ) { return std::isspace(c); } );
str.erase( it, str.end() );
and then you convert your string to an int using std::stoi():
auto aValue = std::stoi( str );
you should also add error checking to your code handling error conditions as described in documentation.
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I am new to c++ programming. I need some help,
I have string :
---- Input : "Name : $$ Enter Your Name2 $$"
I want to extract string between $$ symbols including symbols :
---- Output : "$$ Enter Your Name2 $$"
Please help me.
Regular Expression are very useful in this case.
C++11 has regex library.
#include <string>
#include <regex>
std::string parse_string(const std::string& str) {
static const std::string REGEX_STR = R"__(\$\$(\w|\W)*\$\$)__";
std::regex regex(REGEX_STR);
std::smatch regex_iterator;
if (std::regex_search(str, regex_iterator, regex)) {
return regex_iterator.str();
}
return std::string("");
}
The code can be improved but it should represent a good starting point. Specific case should be handled, for example: more $$*$$ in a string, etc...
Note:
R"__(\$\$(\w|\W)*\$\$)__"; is a raw string in order to make more readable the regex.
Just search the string for the delimiter:
std::string parse_string(const std::string& str, const std::string& delim) {
auto start = str.find(delim);
if (start == std::string::npos)
return "";
auto end = str.find(delim, start + delim.size());
if (end == std::string::npos)
return str.substr(start);
else
return str.substr(start, end - start + delim.size);
}
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My .txt file is like this:
question1 answer1
question2 answer2
question3 answer3
How can I place question1 and answer1 into two separate variables? I can use getLine(), but it will return the question and answer.
If each question is terminated with a question mark then you can write
std::string line;
while ( std::getline( FileStream, line ) )
{
std::istringstream is( line );
std::string question;
std::string answer;
std::getline( is, question, '?' );
question += '?';
std::getline( is, answer );
// some processing of question and answer
}
If there is used some other separator then you need to substitute the question mark for this separator and maybe to remove line
question += '?';
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I have a string like below:
std::string myString = "This is string\r\nIKO\r\n. I don't exp\r\nO091\r\nect some characters.";
Now I want to get rid of the characters between \r\n including \r\n.
So the string must look like below:
std::string myString = "This is string. I don't expect some characters.";
I am not sure, how many \r\n's going to appear.
And I have no idea what characters are coming between \r\n.
How could I use regex in this string?
Personally, I'd do a simple loop with find. I don't see how using regular expressions helps much with this task. Something along these lines:
string final;
size_t cur = 0;
for (;;) {
size_t pos = myString.find("\r\n", cur);
final.append(myString, cur, pos - cur);
if (pos == string::npos) {
break;
}
pos = myString.find("\r\n", pos + 2);
if (pos == string::npos) {
// Odd number of delimiters; handle as needed.
break;
}
cur = pos + 2;
}
Regular expressions are "greedy" by default in most regex libaries.
Just make your regex say "\r\n.*\r\n" and you should be fine.
EDIT
Then split your input using the given regex. That should yield two strings you can combine into the desired result.
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How can I parse a string given by a user and swap all occurrences of the old substring with the new string. I have a function to work with but I am really uncertain when it comes to strings.
void spliceSwap( char* inputStr, const char* oldStr, const char* newStr )
The simplest solution is to use google (First link) here. Also be aware that in C++ we prefer std::string over const char *. Do not write your own std::string, use the built-in one. Your code seems to be more C than C++!
// Zammbi's variable names will help answer your question
// params find and replace cannot be NULL
void FindAndReplace( std::string& source, const char* find, const char* replace )
{
// ASSERT(find != NULL);
// ASSERT(replace != NULL);
size_t findLen = strlen(find);
size_t replaceLen = strlen(replace);
size_t pos = 0;
// search for the next occurrence of find within source
while ((pos = source.find(find, pos)) != std::string::npos)
{
// replace the found string with the replacement
source.replace( pos, findLen, replace );
// the next line keeps you from searching your replace string,
// so your could replace "hello" with "hello world"
// and not have it blow chunks.
pos += replaceLen;
}
}