Question

Java : Please help me correct my code: create a single class (Program11.java) with a main method and some auxiliary methods to input a 2-D array from a disk file, input some “transactions” to change the 2-D array and output the changed 2-D array to another file. Your main method will be minimal (see below). Most of the work will go on in your methods. In main, declare (but do not instantiate) 2-D array. Then call the three methods. The first method will input into the 2-D array and return it. The other two methods are void methods. Here is the primary set of code for main. String [] [] data = input("test1.txt"); process("test2.txt", data); output("output.txt", data); Code: import java.io.File; import java.io.IOException; //import java.io.PrintWriter; import java.util.Scanner; public class Program11A { public static void main(String []args) throws IOException { // Read from the file: String[][] data = input("test1.txt"); process("test2.txt", data); output("output.txt", data); } private static String [ ] [ ] input(String filename)throws IOException { File f1 = new File( filename );//create the file Scanner inf1 = new Scanner( f1 );// set up scanner for the input file int numrows = inf1.nextInt( ); //read # of rows and columns int numcols = inf1.nextInt( ); String [ ] [ ] table = new String [ numrows] [numcols]; for (int x = 0; x < numrows; x++) for (int y = 0; y < numcols; y++) table[x][y] = inf1.next( ); return table; } private static void process( String filename, String [][] table ) { int errorcount = 0; int linecount = 0; File f2 = new File( filename ); //create the file Scanner inf2 = new Scanner( f2 ); // set up scanner for the input file while ( inf2.hasNext() ) { row = inf2.nextInt( ); col = inf2.nextInt( ); str1 = inf2.next( ); str2 = inf2.next( ); lineCount = lineCount + 1; if ( (table [ row ] [ col ]).equals(str1) ) table [ row ] [ col ] = str2; else errorcount++; }// put code here to print to System.out the file name, the total number of lines and the total// number of errors} } private static void output(){ ? } }

Answer 1

//thanks...

//------------------ Program11.java
//package project123;
import java.io.PrintWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Scanner;

public class Program11 {
static String[][] data;
  
public static void main(String[] args) throws IOException {
data = input("test1.txt"); //Read 2d data from the file:
process("test2.txt", data); //make changes in data as per test2.txt file
output("output.txt", data); //save modified data to file
}

private static String[][] input(String filename) throws IOException {
File f1 = new File(filename);
//create the file
Scanner inf1 = new Scanner(f1);
//set up scanner
//for the input file
// read # of rows and columns
int numrows = inf1.nextInt();
int numcols = inf1.nextInt();
  
String[][] table = new String[numrows][numcols];
for (int x = 0; x < numrows; x++) {
for (int y = 0; y < numcols; y++) {
table[x][y] = inf1.next();
System.out.println(table[x][y]); //print table data
}
}
return table;
}
  
private static void process(String filename, String[][] table) throws FileNotFoundException {
int errorcount = 0;
int linecount = 0;
File f2 = new File(filename);
//create the file
Scanner inf2 = new Scanner(f2);
//set up scanner for the input file
int row;
int col;
String str1;
String str2;
int lineCount=0;

// read line by line
while (inf2.hasNext()) {
row = inf2.nextInt(); //read row number
col = inf2.nextInt(); //read col number
str1 = inf2.next(); //read old value string
str2 = inf2.next(); //read new value string
lineCount = lineCount + 1; // increase linecount
if ((table[row][col]).equals(str1)) { // if old value present in table at row col position
table[row][col] = str2; //then replace new value
} else {
errorcount++; //if old value is different than which is present in table then increase errorcount
}
}
//put code here to print to System.out the file name, the total number of lines
//and the total number of errors
System.err.println("File name: " + filename);
System.err.println("Total lines: " + lineCount);
System.err.println("Total errors: "+ errorcount);
}
  
private static void output(String filename, String[][] table) throws FileNotFoundException {
File f3 = new File(filename);
PrintWriter writer = new PrintWriter(f3);
  
int numrows = table.length; //get rows count of table
int numcols = table[0].length; //get cols count of table (length of first row)
  
//write table data to file
for (int x = 0; x < numrows; x++) {
for (int y = 0; y < numcols; y++) {
writer.write(table[x][y] + " ");
}
writer.write("\n");//print newline after each row
}
writer.flush(); //save data to file
writer.close(); //close file
}
  
}
//------------------ end of Program11.java

//-------------- test1.txt
3 2
one two
three four
five six
//-------------- end of test1.txt

//-------------- test2.txt (contains row col oldval newval)
0 0 one onee
0 1 two twoo
1 0 thr three
//-------------- end of test2.txt

//-------------- output.txt NO NEED TO SAVE. It will be generated
onee twoo
three four
five six

//-------------- end of output.txt

//-------- program output
one
two
three
four
five
six
File name: test2.txt
Total lines: 3
Total errors: 1