Please answer question correctly and sow the result of the working code. The act
ID: 3889029 • Letter: P
Question
Please answer question correctly and sow the result of the working code. The actual and demo code is provided .
QUE:Read the input one line at a time and then output the lines in reverse order so that the last line is output first, followed by the second-last line, and so on until the first input line is output last.
Actual code
package comp2402a1;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
public class Part1 {
/**
* Your code goes here - see Part0 for an example
* @param r the reader to read from
* @param w the writer to write to
* @throws IOException
*/
public static void doIt(BufferedReader r, PrintWriter w) throws IOException {
// Your code goes here - see Part0 for an example
}
/**
* The driver. Open a BufferedReader and a PrintWriter, either from System.in
* and System.out or from filenames specified on the command line, then call doIt.
* @param args
*/
public static void main(String[] args) {
try {
BufferedReader r;
PrintWriter w;
if (args.length == 0) {
r = new BufferedReader(new InputStreamReader(System.in));
w = new PrintWriter(System.out);
} else if (args.length == 1) {
r = new BufferedReader(new FileReader(args[0]));
w = new PrintWriter(System.out);
} else {
r = new BufferedReader(new FileReader(args[0]));
w = new PrintWriter(new FileWriter(args[1]));
}
long start = System.nanoTime();
doIt(r, w);
w.flush();
long stop = System.nanoTime();
System.out.println("Execution time: " + 10e-9 * (stop-start));
} catch (IOException e) {
System.err.println(e);
System.exit(-1);
}
}
}
Demo code
package comp2402a1;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
public class Part0 {
/**
* Read lines one at a time from r. After reading all lines, output
* all lines to w, outputting duplicate lines only once. Note: the order
* of the output is unspecified and may have nothing to do with the order
* that lines appear in r.
* @param r the reader to read from
* @param w the writer to write to
* @throws IOException
*/
public static void doIt(BufferedReader r, PrintWriter w) throws IOException {
Set<String> s = new HashSet<>();
for (String line = r.readLine(); line != null; line = r.readLine()) {
s.add(line);
}
for (String text : s) {
w.println(text);
}
}
/**
* The driver. Open a BufferedReader and a PrintWriter, either from System.in
* and System.out or from filenames specified on the command line, then call doIt.
* @param args
*/
public static void main(String[] args) {
try {
BufferedReader r;
PrintWriter w;
if (args.length == 0) {
r = new BufferedReader(new InputStreamReader(System.in));
w = new PrintWriter(System.out);
} else if (args.length == 1) {
r = new BufferedReader(new FileReader(args[0]));
w = new PrintWriter(System.out);
} else {
r = new BufferedReader(new FileReader(args[0]));
w = new PrintWriter(new FileWriter(args[1]));
}
long start = System.nanoTime();
doIt(r, w);
w.flush();
long stop = System.nanoTime();
System.out.println("Execution time: " + 10e-9 * (stop-start));
} catch (IOException e) {
System.err.println(e);
System.exit(-1);
}
}
}
Explanation / Answer
Hi,
the requirement is actually quite simple, you can do a small modification by appending all the lines to an array and then print it backward like below,
public static void doIt(BufferedReader r, PrintWriter w) throws IOException {
List<String> s = new ArrayList<String>();
for (String line = r.readLine(); line != null; line = r.readLine()) {
s.add(line); //adding line ro array list
}
for(int i=s.size()-1;i>=0;i--) { //traversing array list in reverse
w.println(s.get(i));
}
}
Thumbs up if this was helpful, otherwise let me know in comments