如何将数组内容写入输出文件？

Question

I have a program that reads from a input file that has two fields, a day of the week (1-7) and the temperature for that day. It then enters them into an array (highArray, lowArray)and decides the High, Low, total and Average temperatures for each day and writes them to a output file. The problem I am having is how to write the contents of my Arrays to my output file. I can write the day of the week just fine with the line: myOutput.writeInt(dow); I realize that the Output class INT doesn't work with Arrays, so how can I write to file the contents on my Arrays? (highArray, lowArray) BELOW IS MY CODE

package dow;

import java.util.Arrays;

public class DOW
{  
    public static void main(String[] args)
    {
        //  INITIALIZATION
        InputFile myInput = new InputFile("in.txt");
        OutputFile myOutput = new OutputFile("out.txt");

        int dow=0;
        int temperature = 0;
        int[] highArray = new int [8];
        int[] lowArray = new int [8];
        int[] countArray = new int [8];
        int[] totalArray = new int [8];

        // initialize array
        for (dow = 0; dow <8; dow++)
        {
            totalArray [dow]= 0;
            countArray [dow]= 0;
            highArray [dow]= -999;
            lowArray [dow]= 999;            
        }

        while (!myInput.eof())
        {
            dow = myInput.readInt();
            temperature = myInput.readInt();
            if (temperature > highArray[dow]) // High Per Day
            {
                highArray [dow] = temperature;
            }
            if (temperature < lowArray [dow]) // Low Per DAy
            {
                lowArray[dow] = temperature;
            }

            countArray [dow] = countArray[dow] +1;
            totalArray[dow] = totalArray [dow] + temperature;

            System.out.println(dow);
        }
        System.out.println(Arrays.toString(lowArray));
        System.out.println(Arrays.toString(highArray));
        System.out.println(Arrays.toString(totalArray));
        System.out.println(Arrays.toString(countArray));                

        //OUTPUT LOOP             

        for(dow = 1; dow < 8; dow++)
        {
            outputFile.println(highArray[dow]);
        }  

        myOutput.writeInt(dow);

        // myOutput.write(highArray);           
        // myOutput.writeInt(totalArray);
        // myOutput.writeEOL(countArray); 
        // myOutput.writeInt (temperature); 

        myOutput.close();
    }    
}
//END OF MAIN   

Answer 1

• I would highly suggest using BufferedReader and BufferedWriter instead of InputFile and OutputFile .

• As a side note, initializing all values in an int array to 0 is trivial because System.out.print(Arrays.toString(new int[10])); will print out all 0's. int is a primitive type in Java so it is always initialized to 0 and cannot be null . This applies to arrays as well.

Example:

package dow;

import java.util.Arrays;

public class DOW
{
    public static void main(String[] args)
    {
        BufferedReader reader = new BufferedReader(new FileReader("in.txt"));
        BufferedWriter writer = new BufferedWriter(new FileWriter("out.txt"));

        int dow = 0;
        int temperature = 0;
        int[] highArray = new int [8];
        int[] lowArray = new int [8];
        int[] countArray = new int [8];
        int[] totalArray = new int [8];

        // initialize array
        for (dow = 0; dow <8; dow++)
        {
            highArray [dow]= -999;
            lowArray [dow]= 999;
        }

        String nextLine;
        while ((nextLine = reader.nextLine()) != null && !nextLine.isEmpty())
        {
            //DO STUFF
        }
        reader.close();

        writer.write(Arrays.toString(highArray));

        writer.close();
    }
}