Split string using loop to specific length sub-units

Question

I need to split a string into specific lengths, e.g. if user specifies it to units of max length 4, then the loop should run on the original input "0123456789asdf" to get "0123", "4567", "89as", "df".

I can't really figure out the best way to do this - and I need it to be in a loop as further processing needs to be done on each subunit of the strong. TIA.

edit: I do not know how long the original string is, and I only know the size of the chunk it needs to become. Also, I need chunks of the string of the specified length, and the last chunk containing the remainder of the string (if it is less than the specified length).

a similar question that probably could help you: [C++: How do I split a string into evenly-sized smaller strings?](http://stackoverflow.com/questions/8207730/c-how-do-i-split-a-string-into-evenly-sized-smaller-strings) — t.niese, May 23 '13 at 08:46

score 27 · Accepted Answer · answered May 23 '13 at 08:52

27

string str("0123456789asdf");

for (unsigned i = 0; i < str.length(); i += 4) {
    cout << str.substr(i, 4) << endl;
}

answered May 23 '13 at 08:52

Croniak

664
5
4

This does not work if the string is not a multiple of 4 – Miguel Tomás Mar 13 '23 at 07:08

score 0 · Answer 2 · answered May 23 '13 at 08:43

std::string can take a range as its constructor argument (constructor 6). Use it:

char const str[] = "0123456789asdf";
std::string x(str, str + 4); // "0123"

Here, str and str + 4 are pointers to characters into the char array, which are compatible with the ForwardIterator concept. (Pointers are iterators)

Split string using loop to specific length sub-units

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