spliting string in C++

Question

I wonder how to split a string, right before integer. Is it possible? I have written a converter that downloads data from an old txt file, edits it, and saves it in a new form in a new txt file.

For example old file look like:

Every data in new row. New file after convert should look like:

Means that all data after integer should be in a new different line.

My code is included below. Now I have one string as a buf without any white signs:

And I want to split it as shown in the example.

#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

int main () {

    string fileName;

    cout << "Enter the name of the file to open: ";
    cin >> fileName;

    ifstream old_file(fileName + ".txt");
    ofstream new_file("ksiazka_adresowa_nowy_format.txt");

    vector <string> friendsData;
    string buf;
    string data;

    while(getline(old_file, data)) {
        friendsData.push_back(data);
    }
    for(int i=0; i<friendsData.size() ; ++i) {
        buf+=friendsData[i] + '|';
    }
    new_file << buf;

    old_file.close();
    new_file.close();

    return 0;
}

It would be best to show the source string and what you're hoping to split it into as text in the question. — Retired Ninja, May 23 '21 at 18:59
Please show as text the result which you get and compare it to the one you want. I.e. describe in English in which way they are different, this helps to clarify goal and problem. It might help you find an algorithm improvement yourself. — Yunnosch, May 23 '21 at 19:01
[How to split a string in C++](https://www.fluentcpp.com/2017/04/21/how-to-split-a-string-in-c/) — Thomas, May 23 '21 at 19:21

score 0 · Accepted Answer · answered May 23 '21 at 19:47

0

You can try to parse the current string as an int with std::stoi; if it succeeds, you can add a newline to buf. This doesn't exactly split the string, but has the effect you're looking for when you send it to your file, and can be easily adapted to actually cut the string up and send it to a vector.

for(int i=0; i<friendsData.size() ; ++i) {
    try {
      //check to see if this is a number - if it is, add a newline
      stoi(friendsData[i]);
      buf += "\n";
    } catch (invalid_argument e) { /*it wasn't a number*/ }
    buf+=friendsData[i] + '|';
}

(Also, I'm sure you've heard this from someone else, but you shouldn't be using namespace std)

answered May 23 '21 at 19:47

Nick Reed

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Thank you Nick. I read that using namespace std is a bad habit but I am self-taught and its realy hard to find good materials to learn – Bartosz Jurkiewicz May 23 '21 at 19:53
StackOverflow is unironically a pretty good place to learn good coding habits, if only because we tend to be very bold about pointing out bad ones :P In all seriousness, good on you for getting yourself to this point and good luck with your future code! – Nick Reed May 23 '21 at 19:59
1

Haha, I'll try to look here some time then. Thank you again! – Bartosz Jurkiewicz May 23 '21 at 20:10

spliting string in C++

1 Answers1