Easiest way to separate a string by spaces? - c++

Question

It's been a long time since I've used C++, been using Javascript in my free time and now I'm not sure exactly what I remember.
Basically I just need to separate a string into parts by looking at the spaces.
All the links I've seen are homemade functions, but I could have sworn there was a way to do it using the standard library by using streams, but again, I'm having a tough time recalling it and my google results aren't helping either.
Keep in mind that it isn't a stream I am taking from, it's just a string like "Bob Accountant 65 retired" and I have to extract each item in the string to its own data field. I've been messing with ifstreams and ofstreams but I'm not even sure what I'm doing, having forgot the syntax for it.

Answer 1

std::strtok is the C-style way to do it. You might be thinking of using a std::stringstream, e.g.:
#include <sstream>
#include <string>
#include <iostream>
int main() {
std::string input = "foo bar baz quxx\nducks";
std::stringstream ss(input);
std::string word;
while (ss >> word) {
std::cout << word << '\n';
}
}
When run, that displays:
foo
bar
baz
quxx
ducks
If you want to read data from a std::stringstream (or any type of std::istream, really) into a specific data type, you can follow #JerryCoffin's excellent suggestion of overloading the stream operator>> for your data type:
#include <sstream>
#include <string>
#include <iostream>
struct Employee {
std::string name;
std::string title;
int age;
std::string status;
};
std::istream& operator>>(std::istream &is, Employee &e) {
return is >> e.name >> e.title >> e.age >> e.status;
}
int main() {
std::string input = "Bob Accountant 65 retired";
std::stringstream ss(input);
Employee e;
ss >> e;
std::cout << "Name: " << e.name
<< " Title: " << e.title
<< " Age: " << e.age
<< " Status: " << e.status
<< '\n';
}

Answer 2

You can do it without an explicit loop like this:
string s = "Bob Accountant 65 retired";
vector<string> vs;
istringstream iss(s);
copy(istream_iterator<string>(iss), istream_iterator<string>(), back_inserter(vs));
std::copy reads everything from the string stream created on the third line, and pushes it into the vector created on the second line.
Here is a demo on ideone.

Answer 3

From the looks of things, you're trying to read a logical record from a string. For that, I'd do something like this:
struct record {
std::string name;
std::string position;
int age;
std::string status;
};
std::istream &operator>>(std::istream &is, record &r) {
return i >> r.name >> r.position >> r.age >> r.status;
}
This lets you read data from a stringstream to a record of the specified fields. It'll also, incidentally, let you read record objects from other types of streams as well (e.g., from a file using an fstream).