How to seperate string by specific delimiter? - c++

Question

i was wondering if this was a safe way of splitting up string into specific variables. I am currently not getting the correct results. Need newFirstName to contain Joe. newLast name to contain Robbin. NewTeam to contain Oilers and so on. What i am currently getting is nothing in all of the variables except for newFirstname. A point in the correct direction would be much appreciated.
string line = "Joe|Robbin|Oilers|34|23";
char* strToChar = NULL;
char* strPtr = NULL;
string newFirstName = " ";
string newLastName = " ";
string newTeam = " ";
int newAssists = 0;
int newGoals = 0;
sscanf(line.c_str(), "%[^|]s%[^|]s%[^|]s%d|%d",(char*)newFirstName.c_str(), (char*)newLastName.c_str(), (char*)newTeam.c_str(), &newGoals, &newAssists);
Saw lots of great answers but before i did i came up with:
string line = "Joe|Robbin|Oilers|34|23";
char* strToChar = NULL;
char* strPtr = NULL;
string newFirstName = " ";
string newLastName = " ";
string newTeam = " ";
int newAssists = 0;
int newGoals = 0;
int count = 0;
std::string delimiter = "|";
size_t pos = 0;
std::string token;
while ((pos = line.find(delimiter)) != std::string::npos)
{
count++;
token = line.substr(0, pos);
std::cout << token << std::endl;
line.erase(0, pos + delimiter.length());
switch (count)
{
case 1:
newFirstName = token;
break;
case 2:
newLastName = token;
break;
case 3:
newTeam = token;
break;
case 4:
newGoals = atoi(token.c_str());
break;
}
}
newAssists = atoi(line.c_str());

Answer 1

To split a string by some delimiter other than space, the simplest is to use a stringstream along with std::getline, which permits to specify your delimiting character.
std::istringstream iss(line);
std::getline(iss, newFirstName, '|');
std::getline(iss, newLastName, '|');
std::getline(iss, newTeam, '|');
iss >> newAssists;
iss.ignore(); // drop the '|'
iss >> newGoals;
The way you were doing it has many problems indicated in the comments. Most important error was trying to write directly in a std::string's buffer through sscanf, which breaks the most important rule of data encapsulation and leads to undefined behavior.

Answer 2

I was wondering if this was a safe way of splitting up string into specific variables.
My suggestion:
Use std::istringstream and std::getline to tokenize the line.
Pull the numbers of out of the tokens using std::stoi.
Here's a working example.
#include <iostream>
#include <sstream>
#include <string>
int main()
{
std::string line = "Joe|Robbin|Oilers|34|23";
std::istringstream str(line);
std::string newFirstName;
std::string newLastName;
std::string newTeam;
std::string newAssistsString;
std::string newGoalsString;
std::getline(str, newFirstName, '|');
std::getline(str, newLastName, '|');
std::getline(str, newTeam, '|');
std::getline(str, newAssistsString, '|');
std::getline(str, newGoalsString);
// Sanity check.
if (!str )
{
std::cout << "Unable to extract the tokens from the line\n";
return EXIT_FAILURE;
}
int newAssists = std::stoi(newAssistsString);
int newGoals = std::stoi(newGoalsString);
std::cout
<< newFirstName << " "
<< newLastName << " "
<< newTeam << " "
<< newAssists << " "
<< newGoals << std::endl;
return EXIT_SUCCESS;
}
Output
Joe Robbin Oilers 34 23