printf（“％3d，…）在eclipse juno上不起作用

Question

package p;

import java.io.*;
public class fifo {

    public static void main(String[] args) throws IOException 
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int frames = 3, pointer = 0, fault = 0, reflen, def = 0;
        int spaces[];
        int reference[];
        int mem_layout[][];

        System.out.println("Reference String Length: ");
        reflen = Integer.parseInt(br.readLine());


        reference = new int[reflen];
        mem_layout = new int[reflen][frames];
        spaces = new int[frames];
        for(int j = 0; j < frames; j++)
                spaces[j] = 0;

        System.out.println("Reference Numbers: ");
        for(int i = 0; i < reflen; i++)
        {
            reference[i] = Integer.parseInt(br.readLine());      
        }
        System.out.println();
        for(int i = 0; i < reflen; i++)
        {
         int search = -1;
         for(int j = 0; j < frames; j++)
         {
          if(spaces[j] == reference[i])
          {
           search = j;
           def++;
           break;
          } 
         }
         if(search == -1)
         {
          spaces[pointer] = reference[i];
          fault++;
          pointer++;
          if(pointer == frames)
           pointer = 0 ;
         }
            for(int j = 0; j < frames; j++)
                mem_layout[i][j] = spaces[j];
        }

        for(int i = 0; i < frames; i++)
        {
            for(int j = 0; j < reflen; j++)
                //System.out.printf("%3d ", reference);
                System.out.printf("%3d ",mem_layout[j][i]); //ERROR UNDER PRINTF
            System.out.println();
        }

        System.out.println("Fault: " + fault);
        System.out.println("Default: " + def);
        System.out.println("Page Fault Rate: " + fault + "/" + reflen + " = " + ((double)fault/reflen)*100 + "%" );
    }

}

So we are told to continue our work at home. The code is working fine in our computer lab that is using another version of eclipse. Im using a juno and printf doesn't work anymore. Please help the submission is tomorrow i don't know why it doesn't work anymore.

Is juno outdated? I tried doing the eclipse suggestion for removing the error but it produces more error lol :(

Answer 1

In a comment, you say that the error message is this:

The method format(String, Object[])in the type PrintStream is not applicable for the arguments (String, int)

That is odd. However, one possible explanation is that your Eclipse settings have selected a really old version of Java. Prior to Java 1.5, auto-boxing is not supported., and that would prevent the compiler from autoboxing the int to an Integer .

Start Eclipse and open up Window>Preferences. Select the Java>Compiler preferences. Look at that the "Compiler compliance level" setting is, and change it to "1.8".

Then use Project>Clean to recompile everything.

---

You could also change this:

System.out.printf("%3d ", mem_layout[j][i]);

to this:

System.out.printf("%3d ", new Object[]{
                             Integer.valueOf(mem_layout[j][i])});

which makes the source code compatible with old Java compilers. But that's a poor solution, IMO.

Answer 2

• Try System.out.format(); instead of System.out.printf();
• Try installing another version of Eclipse that they're using at labs
• And please, write us what error/exception is Eclipse showing