CODEWITHSUNDEEP
c++matrix
Adam
Adam

Reputation: 11

Read numbers from file based on their position as matrix in c++

I have a big file with numbers and I want to extract numbers based on their positions(row, column). For example, if I want to process only the first 3 rows and 3 columns which are 9 numbers. The program print the 9 numbers in the first row. I want to go the next line once the column index is 4. How to do this in c++. Here is what I have been don so far:

#include <iostream>
#include <fstream>
using namespace std;

const int NROWS = 3;
const int NCOLS = 3;
int main()
{
   ifstream data;

   double Numbers[NROWS][NCOLS];

   double Num;

   data.open("Input.txt");
   for (int i = 0; i<NROWS; ++i)
   {
          for (int j = 0; j<NCOLS; ++j)
       {
           data >> Num;
           Numbers[i][j]=Num;
           cout << Numbers[i][j] << endl;
       }
   }
   data.close();
   return 0;
  }

Upvotes: 0

Views: 378

Answers (1)

3CxEZiVlQ
3CxEZiVlQ

Reputation: 38893

You should skip lines after each NCOLS column numbers are read.

#include <iostream>
#include <fstream>
using namespace std;

const int NROWS = 3;
const int NCOLS = 3;
int main()
{
   ifstream data;

   double Numbers[NROWS][NCOLS];

   double Num;

   data.open("Input.txt");
   for (int i = 0; i<NROWS; ++i)
   {
       for (int j = 0; j<NCOLS; ++j)
       {
           data >> Num;
           Numbers[i][j]=Num;
           cout << Numbers[i][j] << endl;
       }
       std::string skip;
       std::getline(data, skip);
   }
   data.close();
   return 0;
}

Upvotes: 1

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