Split string by a character?

Question

How can I split a string such as "102:330:3133:76531:451:000:12:44412 by the ":" character, and put all of the numbers into an int array (number sequence will always be 8 elements long)? Preferably without using an external library such as boost.

Also, I'm wondering how I can remove unneeded characters from the string before it's processed such as "$" and "#"?

Solution 1

stringstream can do all these.

1. Split a string and store into int array:

   string str = "102:330:3133:76531:451:000:12:44412";
   std::replace(str.begin(), str.end(), ':', ' ');  // replace ':' by ' '
   
   vector<int> array;
   stringstream ss(str);
   int temp;
   while (ss >> temp)
       array.push_back(temp); // done! now array={102,330,3133,76531,451,000,12,44412}
   

2. Remove unneeded characters from the string before it's processed such as $ and #: just as the way handling : in the above.

PS: The above solution works only for strings that don't contain spaces. To handle strings with spaces, please refer to here based on std::string::find() and std::string::substr().

Solution 2

The standard way in C is to use strtok like others have answered. However strtok is not C++-like and also unsafe. The standard way in C++ is to use std::istringstream

std::istringstream iss(str);
char c; // dummy character for the colon
int a[8];
iss >> a[0];
for (int i = 1; i < 8; i++)
    iss >> c >> a[i];

In case the input always has a fixed number of tokens like that, sscanf may be another simple solution

std::sscanf(str, "%d:%d:%d:%d:%d:%d:%d:%d", &a1, &a2, &a3, &a4, &a5, &a6, &a7, &a8);

Solution 3

I had to write some code like this before and found a question on Stack Overflow for splitting a string by delimiter. Here's the original question: link.

You could use this with std::stoi for building the vector.

std::vector<int> split(const std::string &s, char delim) {
    std::vector<int> elems;
    std::stringstream ss(s);
    std::string number;
    while(std::getline(ss, number, delim)) {
        elems.push_back(std::stoi(number));
    }
    return elems;
}

// use with:
const std::string numbers("102:330:3133:76531:451:000:12:44412");
std::vector<int> numbers = split(numbers, ':');

Here is a working ideone sample.

Solution 4

True ! there's no elven magic

Its kinda answered here too

#include <cstring>
#include <iostream>
#include<cstdlib>
#include<vector>

int main() 
{
    char input[100] = "102:330:3133:76531:451:000:12:44412";
    char *token = std::strtok(input, ":");
    std::vector<int> v;

    while (token != NULL) {
        v.push_back( std::strtol( token, NULL, 10 ));
        token = std::strtok(NULL, ":");
    }

    for(std::size_t i =0 ; i < v.size() ; ++i)
        std::cout << v[i] <<std::endl;
}

Demo Here

Solution 5

#include <stdio.h>
#include <string.h>

int main ()
{
  char str[] ="102:330:3133:76531:451:000:12:44412";
  char * pch;
  printf ("Splitting string \"%s\" into tokens:\n",str);
  pch = strtok (str,":");
  while (pch != NULL)
  {
    printf ("%s\n",pch);
    pch = strtok (NULL, ":");
  }
  return 0;
}

View more solutions