If statement not changing initialized value

Question

My enum type is not being changed from its default "null" value when displayed by a basic toString method. When the user inputs JPG,GIF, etc the if statement is supposed to recognize that the inputted string corresponds to enum. Why is the if statement not taking the user's input and converting it to match the enum?

public static void processPhotos()
{
    String value;
    String size;
    String name;
    String strType;
    double dSize;
    String photographer;
    int iValue = 1;
    Scanner kb = new Scanner(System.in);


    while(iValue>0)
    {
        System.out.print("Enter the Photo's name.");
        name = kb.nextLine();
        System.out.print ("\nEnter the Photo's type(JPG, GIF, PNG, BMP, or OTHER).");
        strType = kb.nextLine();
        strType = strType.toUpperCase ( );
        if(strType == "JPG")
        {
            type = Type.JPG;
        }
        if(strType == "GIF")
        {
            type = Type.GIF;
        }
        if(strType == "PNG")
        {
            type = Type.PNG;
        }
        if(strType == "BMP")
        {
            type = Type.BMP;
        }
        if(strType == "OTHER")
        {
            type = Type.OTHER;
        }

        System.out.print("\nEnter the Photo's size(IN Megabytes)");
        size = kb.nextLine();
        dSize = Double.parseDouble (size);
        System.out.print("\nEnter the Photo's Photographer");
        photographer = kb.nextLine();
        Photo p = new Photo(name,type,dSize,photographer);
        System.out.print (p.toString());
        System.out.print("\n\nEnter an integer greater than zero to continue. Enter ZERO to end.");
        value = kb.nextLine();
        iValue = Integer.parseInt(value);

    }
}

@user2909717 if my answer is helpful then you select my answer — Ashish, Feb 17 '14 at 08:43

score 1 · Answer 1 · answered Feb 17 '14 at 07:54

1

Compare the strings with this approach instead.

if(strType.equals("JPG"))

Then you compare the two strings for having the same value.

The == compare that the two strings are in fact the same object stored in memory, of which they are not.

answered Feb 17 '14 at 07:54

Niels Bech Nielsen

4,777
1
21
44

Ashish · Answer 2 · 2014-02-17T07:55:31.447

0

if(strType == "JPG")

it should be :

if(strType.equalsIgnoreCase( "JPG"))

so for every == change it to equalsIgnoreCase or equals

edited Feb 17 '14 at 07:55

answered Feb 17 '14 at 07:52

Ashish

1,943
2
14
17

Yap as String is object – Subhrajyoti Majumder Feb 17 '14 at 07:53

score 0 · Answer 3 · answered Feb 17 '14 at 07:53

0

You have to use equals instead of ==

type == Type.JPG // comparing references
Type.JPG.equals(type) //Compares valus

answered Feb 17 '14 at 07:53

Zeeshan

11,851
21
73
98

score 0 · Answer 4 · answered Feb 17 '14 at 07:57

To compare strings you need to use.equals instead of == So your code should be if(strType.equals("JPG"))

public static void processPhotos()
{
    String value;
    String size;
    String name;
    String strType;
    double dSize;
    String photographer;
    int iValue = 1;
    Scanner kb = new Scanner(System.in);


    while(iValue>0)
    {
        System.out.print("Enter the Photo's name.");
        name = kb.nextLine();
        System.out.print ("\nEnter the Photo's type(JPG, GIF, PNG, BMP, or OTHER).");
        strType = kb.nextLine();
        strType = strType.toUpperCase ( );
        if(strType.equas("JPG"))
        {
            type = Type.JPG;
        }
        if(strType.equals("GIF")).
        {
            type = Type.GIF;
        }
        if(strType.equals("PNG"))
        {
            type = Type.PNG;
        }
        if(strType.equals("BMP"))
        {
            type = Type.BMP;
        }
        if(strType.equals("OTHER"))
        {
            type = Type.OTHER;
        }

        System.out.print("\nEnter the Photo's size(IN Megabytes)");
        size = kb.nextLine();
        dSize = Double.parseDouble (size);
        System.out.print("\nEnter the Photo's Photographer");
        photographer = kb.nextLine();
        Photo p = new Photo(name,type,dSize,photographer);
        System.out.print (p.toString());
        System.out.print("\n\nEnter an integer greater than zero to continue. Enter ZERO to end.");
        value = kb.nextLine();
        iValue = Integer.parseInt(value);

    }
}

score 0 · Answer 5 · answered Feb 17 '14 at 08:02

You dont need a switch case/condition check for this , you can convert your user input to enum as follows:

enum Type {
        JPG, GIF, PNG;
    }

    public static void main(String[] args) throws Exception {
        String input = "GIF";
        Type type = Type.valueOf(input);
        System.out.println(type);

    }

score 0 · Answer 6 · edited May 23 '17 at 10:29

0

You should use equals instead. Here is a thread discussing why you should do that.

How do I compare strings in Java?

briefly

== tests for reference equality.

.equals() tests for value equality.

edited May 23 '17 at 10:29

Community

1
1

answered Feb 17 '14 at 08:06

Mohamed Ali JAMAOUI

14,275
14
73
117

score 0 · Answer 7 · answered Feb 17 '14 at 09:04

0

override equals() method of Object class while comparing two string .

ex : str1.equals(str2);

answered Feb 17 '14 at 09:04

pavan kumar

108
4

Why you want to override equals() method of Object class? equals() method is already been overriden by String class for String comparison. You just have to invoke it on a string object – Zeeshan Feb 17 '14 at 09:19

score -1 · Answer 8 · answered Feb 07 '17 at 23:31

Make your live easier and Parse the Enum. You won't have to write that much code and if the enum changes, you don't have to change the method. Also you can choose a default Type of your choise or do anything else if strType is not a Type in the Enum.

if (Enum.TryParse<Type>(strType, out type))
    type = Type.OTHER

If statement not changing initialized value

8 Answers8