Reading Numbers from a Text File, Line by Line

   

import java.io.FileReader;
import java.io.IOException;
import java.io.LineNumberReader;
import java.io.StreamTokenizer;

public class SumLine {
  
  public static void main(String[] a)throws IOException {
      sumLines("file.txt");
  }
  static void sumLines(String filename) throws IOException {
    LineNumberReader lnr = new LineNumberReader(new FileReader(filename));
    lnr.setLineNumber(1);
    StreamTokenizer stok = new StreamTokenizer(lnr);
    stok.parseNumbers();
    stok.eolIsSignificant(true);
    stok.nextToken();
    while (stok.ttype != StreamTokenizer.TT_EOF) {
      int lineno = lnr.getLineNumber();
      double sum = 0;
      while (stok.ttype != StreamTokenizer.TT_EOL) {
        if (stok.ttype == StreamTokenizer.TT_NUMBER)
          sum += stok.nval;
        stok.nextToken();
      }
      System.out.println("Sum of line " + lineno + " is " + sum);
      stok.nextToken();
    }
  }
}

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Reading Numbers from a Text File, Line by Line : File Reader « File Input Output « Java

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