CODEWITHSUNDEEP
c++
PanosCr
PanosCr

Reputation: 3

How to transfer a table from a text file to C++

I'm fairly new to C++ and I need some help. The input is a text file that looks something like that:

5

1 2 3 4 5

1 2 3 4 5 

1 2 3 4 5

1 2 3 4 5 

1 2 3 4 5

In the first line there is an integer N and then there are N lines with N numbers. How can I read the file and create a table (a 2d array)? Like that: [ [1,2,3,4,5], [1,2,3,4,5], [1,2,3,4,5], [1,2,3,4,5], [1,2,3,4,5], ].

That's my code right now:

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

int main()
{
    string fname;
    cout << "Enter the file name" << endl;
    cin >> fname;

    ifstream MyReadFile(fname);
    string myText;

    int N;
    int i = 0;

    while (getline(MyReadFile, myText))
    {
        if (i == 0)
        {
            N = stoi(myText);
        }

        i += 1;
    }

    MyReadFile.close();
}

I know it looks bad, I've been learning C++ for only a week. Thanks in advance.

Upvotes: 0

Views: 318

Answers (1)

StPiere
StPiere

Reputation: 4263

You don't need explicitely convert string to text via stoi. istream::operator>> does that for you:

ifstream in(filename); 

int n;
in >> n;
vector<vector<int>> v(n, vector<int>(n));

for (int i = 0; i < n; ++i)
    for (int j = 0; j < n; ++j)
        in >> v[i][j];

Upvotes: 4

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