Accessing Array Index OutSide The for Loop

Question

I have a problem in accessing the the value of i outside the for loop. At first I want to get 5 Names From User and after that wants to print all of them on the Screen using Arrays. Please Help.

public class Student {

    public static void main(String[] args) {

        Scanner input=new Scanner(System.in);

        String []Name;
        Name=new String[5];

        System.out.println("Please Enter The Names Of 5 Students: ");

        //INPUTS 5 STUDENTS NAME FROM USER
        for(int i=0; i<5; i++)
        {
            System.out.println("Enter The Name of student: "+(i+1));
            Name[i]=input.nextLine();
        }

        //Prints All The Students Names
        System.out.println("The Name of student: "+(i+1)+" is : "+ Name[i]);
    }
}

MD Sayem Ahmed · Accepted Answer · 2012-03-18 07:32:29Z

3

To print all the student's name, do the same thing as taking input -

// Prints all the student's name
for(int j=0; j<5; j++)
{
    System.out.println("The name of the " + 
                        (j+1) + "-th student is: " + 
                        Name[j]);
}

By the way, you won't be able to access the variable i outside of the input loop. It is scoped inside that loop.

edited Mar 18, 2012 at 7:32

answered Mar 18, 2012 at 7:27

MD Sayem Ahmed

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Comments

Jon Skeet · Accepted Answer · 2012-03-18 07:28:08Z

1

What do you expect the value of i to be outside the loop? The variable isn't in scope any more... logically speaking, it doesn't exist.

It sounds like you want a second loop to print the values after you've input them. You've already got one loop for the input, so you should be able to model your second loop on that.

answered Mar 18, 2012 at 7:28

Jon Skeet

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Comments

Rameshwar.S.Soni · Accepted Answer · 2012-03-18 07:29:51Z

0

You are having problem in accessing the value of i because you are printing the values outside the loop. So put that in loop as done by the above poster

answered Mar 18, 2012 at 7:29

Rameshwar.S.Soni

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kundan bora · Accepted Answer · 2012-03-18 07:32:40Z

0

Scope of identifier "i" is limited to for loop that means int "i" is only exist within the for loop when code exit from for loop "i" is destroyed.

Second thing is if you widen your "i" scope by declaring this outside the for loop, You still not get all the array element because you are not looping each of element. You need to loop through each element.

answered Mar 18, 2012 at 7:32

kundan bora

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Rushdi Shams · Accepted Answer · 2012-03-18 07:33:27Z

0

Outside the loop, the value of i is 5 but your array is of 5 elements (you already filled its 0-4th index inside the loop).

answered Mar 18, 2012 at 7:33

Rushdi Shams

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Comments

Dunes · Accepted Answer · 2012-03-18 07:46:27Z

0

Not an answer, as I think Jon's answer is good. But here are a couple of style guidelines for Java.

Declaring arrays

In an array declaration in java the [] is attached to the type and not variable.

eg.

String[] arr; // not String []arr;

This is because arrays are first class objects not pointers (like in C/C++). As such all variables in a declaration will be of exactly the same type.

That is:

int[] arr1, arr2; // declares two int arrays

As opposed to C/C++ where this would instead declare one array of ints called arr1 and one int called arr2 (well technically it wouldn't as the syntax is broken for C/C++).

Variable names

Convention for variable names in Java is to use camel case and start with a lowercase letter. You'll notice in your question the syntax highlighter highlighted Names in blue. This is because it thought Names was a class name and not a variable name. For classes, the convention is to use camel case again, but start with an uppercase letter.

eg.

MyClass myVariable;

answered Mar 18, 2012 at 7:46

Dunes

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2 Comments

M Platvoet Over a year ago

not entirely true: int[] arr[]; is valid to, leaves you an int[][]

Dunes Over a year ago

@MPlatvoet So the initial type specifies a minimum dimension?

Exorcist · Accepted Answer · 2012-03-18 08:05:34Z

If a variable is declared inside a loop,its scope is only in the loop. What you should have done is something like this :

public class Student {

public static void main(String[] args) {

    Scanner input=new Scanner(System.in);

    String []Name=new String[6];
    int i;

    System.out.println("Please Enter The Names Of 5 Students: ");

    //INPUTS 5 STUDENTS NAME FROM USER
    for(i=1; i<=5; i++)
    {
        System.out.println("Enter The Name of student : "+i+" : ");
        Name[i]=input.nextLine();
    }

    for(i=1;i<=5;i++)
    System.out.println("The Name of student: "+(i+1)+" is : "+ Name[i]);
}
}

Furthermore,notice that I have declared the array of size 6.This is done so as to take the name of ths student from serial number 1. That is the value at Name[0] would be some garbage value or \you can assign it to whatever value you want.Who cares? We are using the array from its 1st position.

The first value is in Name[1] and the last value is in Name[5].

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