Only else statement of if...else ladder is being executed no matter what the input. Why is this happening?

Question

Given below is some code to sort the contents of a file in ascending or descending order wher in is an object of the Scanner class

public void sortFile(String fileName)throws IOException
{
    FileReader fin=new FileReader("C:\\File Handling\\"+fileName+".txt");
    BufferedReader bin=new BufferedReader(fin);

    String[] str=new String[100];

    int i=0;
    while((str[i]=bin.readLine())!=null)
        i++;

    Comparator<String> c=Collections.reverseOrder();

    System.out.println("\nIf you want to sort in descending order, enter A");
    System.out.println("If you want to sort in ascending order, enter D");
    System.out.println("Using any other characters or strings will produce an error and exit his method\n");

    String opt=in.next();
    if(opt=="A"||opt=="a")
        Arrays.sort(str,0,i);
    else if(opt=="D"||opt=="d")
        Arrays.sort(str,0,i,c);
    else
    {
        System.out.println("Wrong option");
        main();
    }

    FileWriter fout=new FileWriter("C:\\File Handling\\"+fileName+".txt");
    BufferedWriter bout=new BufferedWriter(fout);
    PrintWriter pout=new PrintWriter(bout);

    for(i=0;i<str.length;i++)
    {
        if(str[i]!=null)
            pout.println(str[i]);
    }

    pout.flush();
    pout.close();
}

However upon execution of this code, no matter what value I assign to the variable opt, I always get a message of "Wrong option" and get redirected to the main() method.

Why is this happening?

Does anyone have any other suggestions to improve this code in any other aspect?

possible duplicate of [How do I compare strings in Java?](http://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) — Pradeep Simha, Nov 16 '14 at 05:14

Subhrajyoti Majumder · Accepted Answer · 2014-11-16T05:18:16.807

1

if(opt.equals("A")||optopt.equals("a")){...}
else if(opt.equals("D")||opt.equals("d")){...}
else{...}

String is object so for equaling two string's required equals method.

Find a good post - What’s the difference between equals() and ==?

edited Nov 16 '14 at 05:18

answered Nov 16 '14 at 05:13

Subhrajyoti Majumder

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Yes, you need to use the equals() method instead of using == to compare strings. == works for primitives, or for testing to see if two objects are the same instance. – Jamie Nov 16 '14 at 05:15

Only else statement of if...else ladder is being executed no matter what the input. Why is this happening?

1 Answers1