String

Is there a function to split a string by a character like if you use that on a string: "do killing", it splits it to "do" and "killing" strings

not sure if there's a library function to do that but something like this will work

Code:

---

#include <iostream>
#include <string>
#include <cctype>
#include <vector>

using namespace std;

//returns true if c is a space
bool space ( char c ){

            return isspace(c);

    }
//returns true if c is not a space
bool not_space ( char c ){

                return !isspace(c);

    }
//split function
vector<string> split ( string s ){
                      //i will be at the beginning of the string
                      string::iterator i = s.begin();

                      //vector of the words that we will return
                      vector<string> ret;

                      //run the loop until we reach the end
                      while ( i != s.end() ){
                            //find the first nonspace character from i
                            i = find_if ( i, s.end(), not_space );
                           
                            //if i found a nonspace character
                            if ( i != s.end() ){

                                //j will be at the first space character
                                      string::iterator j = i;

                                  //find the space, if there is not, s.end() will be returned
                                j = find_if ( i, s.end(), space );

                                //push back the string delimited by  [i, j)
                                ret.push_back ( string ( i, j ) );

                                //set i equal to j to look through the rest of the string
                                i = j;
                   
                              }

                      }

                      return ret;

                }

int main(){

        string s = "    hello world";

        vector<string> vec = split(s);

        cout << vec[0] << endl << vec[1];

        return 0;

    }

---

That will output

hello
world


but if you're just receiving input, either from a file or from cin, the input stream will ignore the whitespace unless you say so by using noskipws

Code:

---

#include <iostream>
#include <string>

using namespace std;

int main(){

        string s;

        while ( cin >> s ){

                cout << s << endl;

        }

        return 0;

    }

---

that will work just fine also. try running it and typing something like "hey there stranger" or something, and you'll see that the output is

hey
there
stranger

Thanks

Code:

---

#include <iostream>
#include <string>
#include <sstream>
#include <vector>

using namespace std;

int main()
{
        vector<string> tokens;
        string s1 = ("Split Me Up! Word1 Word2 Word3");
        string s2;
        stringstream ss ( s1 );
        while ( ss >> s2 )
        {
                cout << s2 << endl;
        }
        cin.get();
        return 0;
}

---

Or you could use the good old strtok method which also allows you to split a string. strtok is a little more situational I think, but it should be perfect to split "do killing" into "do" and "killing"

How do I: Seperate a string into tokens (C++)

Here are my string splitting and trimming functions.

Code:

---

#include <iostream>
#include <string>
using namespace std;

////////////////////////////////////////////////////////////////////////////////

string& trim_string(string &str);
string& trim_string(string &str,
                    const string &pre_chars,
                    const string &post_chars);
string split_string(string &str,
                    const string &delim_chars,
                    bool trim_space = true);

////////////////////////////////////////////////////////////////////////////////

// trim surrounding space from a string
string& trim_string(string &str) {
  return trim_string(str, " \t\r\n", " \t\r\n");
}

// trim specified characters around a string
string& trim_string(string &str,
                    const string &pre_chars,
                    const string &post_chars)
{
  // only do something if the string is not empty
  if (str.length() > 0) {   
    string::size_type first = str.find_first_not_of(pre_chars);
    string::size_type last = str.find_last_not_of(post_chars);
   
    // if none of the pre_chars are located, just clear the string
    if (first == string::npos)
      str.erase();
    // otherwise grab a substring after pre_chars and before post_chars
    else
      str = str.substr(first,
        first != string::npos && last != string::npos
        ?
          last - first + 1
        :
          string::npos);
  }
 
  return str; 
}

////////////////////////////////////////////////////////////////////////////////

// this splits part of a string from str using any of delim_chars
// to do the tokenizing
string split_string(string &str,
                    const string &delim_chars,
                    bool trim_space)
{
  string split;

  // search for any of the delim_chars in the source string
  string::size_type n = str.find_first_of(delim_chars);
  // if none were found, split the entire string apart and leave
  // the source empty
  if (n == string::npos) {
    split = str;
    str.erase();
  }
  // otherwise separate the string apart from the source, insuring
  // that we drop the delimiting character
  else {
    split = str.substr(0, n);
    str = str.substr(n + 1);
  }

  // if the user desires, we trim the space around the split
  // string and the source string
  if (trim_space) {
    trim_string(split);
    trim_string(str);
  }

  return split;
}

////////////////////////////////////////////////////////////////////////////////

// here is an example
int main() {
  string str = "Peter Griffin, Quahog, Rhode_Island";
  while (str.length() > 0) {
    string next = split_string(str, ", ");
    cout << next << endl;
  }
  return 0;
}

---

Here's the output:

Quote:

---

Originally Posted by output

Peter
Griffin
Quahog
Rhode_Island

---

How to do it with a char* variable?

Very carefully :).
Very similary but you would use strcpy and such.
Oh and lucky gigity gigity gigity alright!