Extract integer arrays from delimiter splitted string using C++

Question

I am trying to extract integer sequences from a string in C++, which contains a certain delimiter, and create arrays with them:

The input is in the following format:

<integer>( <integer>)+(<delimiter> <integer>( <integer>)+)+

Example: 1 2 3 4; 5 6 7 8; 9 10 (Here the delimiter is ;)

The result should be three integer arrays, containing: [1, 2, 3, 4], [5, 6, 7, 8] and [9, 10]

What I've tried so far is using istringstream, because it already splits them by whitespace, but I didn't succeed:

#include <iostream>
#include <sstream>

using namespace std;

int main() {
    string token;
    cin >> token;

    istringstream in(token);

    // Here is the part that is confusing me
    // Also, I don't know how the size of the newly created array
    // will be determined

    if (!in.fail()) {
        cout << "Success!" << endl;
    } else {
        cout << "Failed: " << in.str() << endl;
    }

    return 0;
}

Thomas Matthews · Accepted Answer · 2017-11-25 15:39:31Z

1

My suggestion is to read until the ';' using std::getline, then parse the string using std::istringstream:

std::string tokens;
std::getline(cin, tokens, ';');
std::istringstream token_stream(tokens);
std::vector<int> numbers;
int value;
while (token_stream >> value)
{
  numbers.push_back(value);
}

answered Nov 25, 2017 at 15:39

Thomas Matthews

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Jake Freeman · Accepted Answer · 2017-11-25 16:13:36Z

1

To carry off the previous answer is to read until the ';' using std::getline, then parse the string using std::istringstream down to its spaces:

std::string tokens;
std::getline(cin, tokens);
std::istringstream token_stream(tokens);
std::vector<string> arr;
vector<vector<int>> toReturn
string cell;
while (getline(token_stream, cell, ';')
{
    arr.push_back(cell);
}
for(int i = 0; i<arr.size(); i++)
{
     istringstream n(arr[i]);
     vector<int> temp;
     while(getline(n, cell, ' ') temp.push_back(atof(cell));
     toReturn.push_back(temp);
}

answered Nov 25, 2017 at 16:13

Jake Freeman

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