Split a string inside a class constructor

Question

I have a class with 2 data members: size and an array of ints (dynamically allocated). The purpose of the class is to create an array of a size and fill it with values. The task is to create a constructor that takes a string as its parameter, but the string looks like this: "12|13|14|15" etc. I have searched this but all the solutions are a little too complicated, as they involve vectors and we haven't started with vectors yet. I basically want to put these numbers into the array of ints, 1 by 1 and also find out the size of the array. How can I do that? I tried messing with getline and stringstream but that gave me a load of errors. My code looks like this.

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

class IntArrays {
private:
        static int objcount;
    int size;
public:
        int *arrayints;
        const static int objcountf();
    IntArrays(int);
    IntArrays(const IntArrays &p){
                size = p.size;
                for (int i = 0;i <size;i++){
                    arrayints[i] = p.arrayints[i];
                    }
                    }
IntArrays(std::string f){
                      // ignore the other constructors, this is the constructor that is giving me trouble
                      int counter =0;
                 istringstream inStream(f);
                 string newstring;
                 while (getline(iss,newstring, '|')){
                       arrayints[counter] = stoi(newstring);
                       counter++;}
void enternums();
(note that this is only the header file, and that the current string constructor I have there does not work.

Answer 1

I will try to have a recursion for that =p Sorry that I cannot provide a c++ version =p.. This is a java version i guess.

list parse(string data, list base) {
    if (data.length > 0) {
        string s = data.subStr(0,1);
        if (s == "|") {
            base.push(0); //set the initial value for a new value
        } else {
            int i = parseInt(s);
            int result = base.pop()*10 + i; //recalculate the result
            base.push(result);
        }
        return parse(data.subStr(1),base); //recursion
    } else {
        return base; //return the result
    }
}

Answer 2

As Joachim pointed out, you do not initialize the pointer. Unfortunately, you do not have the size of the array before the allocation, so you are left with a few solutions:

1. process the input twice (really bad if you have a large number of entries); On the first pass, count the inputs. Then allocate the array, then read them again, into the allocated array.

2. read the inputs into a linked list; Each element in the list would hold a value, and the address of the next element.

3. Preallocate a block of memory and hope it is large enough to read the entire array. If it is not, reallocate a larger block and copy the already read values into it, then discard the initial block (this is what std::vector does).

Answer 3

This code is my version. I prefer to use a vector rather than a raw array.

Class definition:

class IntArrays {
public:
    IntArrays(const string&, const char&);
    const vector<int>& data() { return _data; }
    const int size() { return _data.size(); }

private:
    vector<int> _data;
};

The following is the constructor implementation:

IntArrays::IntArrays(const string& str, const char& delimiter) {
    string buff;
    for(auto& n:str) {
        if(n != delimiter) buff+=n; else
        if(n == delimiter && buff != "") {
            _data.push_back(stoi(buff));
            buff = "";
        }
    }
    if(buff != "") _data.push_back(stoi(buff));
}

And then we just use the class:

IntArrays a("1|4|9|6|69", '|');
vector<int> da = a.data();

IntArrays b("1,4,9,6,69", ',');
vector<int> db = b.data();