Splitting string with colons and spaces? - c++

Question

So I've made my code work for separating the string:
String c;
for (int j = 0 ; j < count; j++) {
c += ip(ex[j]);
}
return c;
}
void setup() {
Serial.begin(9600);
}
I have had no luck with this, so any help would be greatly appreciated!

Answer 1

I would simply add a delimiter to your tokenizer. From a strtok() description the second parameter "is the C string containing the delimiters. These may vary from one call to another".
So add a 'space' delimiter to your tokenization: ex[i] = strtok(NULL, ": "); trim any whitespace from your tokens, and throw away any empty tokens. The last two shouldn't be necessary, because the delimiters won't be part of your collected tokens.

Answer 2

I'd suggest using <regex> library if the compiler of yours supports C++11.
#include <fstream>
#include <iostream>
#include <algorithm>
#include <iterator>
#include <regex>
const std::regex ws_re(":| +");
void printTokens(const std::string& input)
{
std::copy( std::sregex_token_iterator(input.begin(), input.end(), ws_re, -1),
std::sregex_token_iterator(),
std::ostream_iterator<std::string>(std::cout, "\n"));
}
int main()
{
const std::string text1 = "...:---:...";
std::cout<<"no whitespace:\n";
printTokens(text1);
std::cout<<"single whitespace:\n";
const std::string text2 = "..:---:... ..:---:...";
printTokens(text2);
std::cout<<"multiple whitespaces:\n";
const std::string text3 = "..:---:... ..:---:...";
printTokens(text3);
}
The description of library is on cppreference. If you are not familiar with regular expressions, the part in the code above const std::regex ws_re(":| +"); means that there should be either ':' symbol or (or in regular expressions denoted by pipe symbol '|') any amount of whitespaces ('+' stands for 'one or more symbol that stands before the plus sign'). Then one is able to use this regular expression to tokenize any input with std::sregex_token_iterator. For more complex cases than whitespaces, there is wonderful regex101.com.The only disadvantage I could think of is that regex engine is likely to be slower than simple handwritten tokenizer.