Thread: Getting 1 error in my menu driven code for students add,delete and list.

 
 
import java.util.ArrayList;
import java.util.Scanner;
	public class StudentMenu{
	    public static void main(String[] args)
	    {
 
	    	ArrayList<Student> studentlist = new ArrayList<Student>();
	        Student nextStudent;
	        int select;
 
 
	        String fName;
	        String sName;
	        String grade;
	        int mark;
 
 
 
	        do{
	            System.out.println("Please choose and option:[1-4].\n"+
	                    "1 - Add a Student.\n"+
	                    "2 - Delete A Student.\n"+
	                    "3 - List All Students.\n"+
	                    "4 - Exit.");
	            Scanner keyboard = new Scanner(System.in);
	            select=keyboard.nextInt();
 
	            switch(select)
	            {	            
	            case 1:	   
	            	System.out.print("Please enter no of students ");
                    int numstudents = keyboard.nextInt();
                    keyboard.nextLine();
 
				for (int i=0; i<numstudents; i++)
	                {
	                    System.out.print("Please enter students first name: ");
	                    fName = keyboard.next();
	                    System.out.println();
 
 
	                    System.out.print("Please enter students surname: ");
	                    sName  = keyboard.next();
	                    System.out.println();   
 
	                    System.out.print("Please enter your exam mark: ");
	                    mark  = keyboard.nextInt();
	                    System.out.println();
 
	                    nextStudent = new Student (fName,sName,mark);
	                    studentlist.add(nextStudent);
 
 
	                }
	                break;
	            case 2:
	            {
	            	System.out.print("Please enter student you want to delete's first name: ");
                    fName = keyboard.next();
                    System.out.println();
 
 
                    System.out.print("Please enter students surname: ");
                    sName  = keyboard.next();
                    System.out.println();   
 
                    for (Student s: studentlist)
                    {
 
                    	if	( (s.getFname().equals(fName)) && (s.getSname().equals(sName)))
 
                    	//(s.getFname().equals(fName)) && ((s.getSname().equals(sName))
                    			studentlist.remove(s);
                    }
	            }
	            break;
	            case 3:
	            {
	            	 for (Student s: studentlist)
	                    {
	            		 System.out.println(s);
	                    }
	            }
	            break;
 
 
	            case 4:
	            {
	            	 System.out.println("Goodbye");
	            }
	            break;
	            {	 
	            Default:
	            {
 
	            	System.out.println("Invalid Selection, Plaese try again");
	            }
	            break;
 
	              }while (select!=4);
	            }   
 
	    }
	        }
 
	    }

The error is with the 3rd last } bracket,This is what the error is saying.

Exception in thread "main" java.lang.Error: Unresolved compilation problem:
Syntax error, insert "while ( Expression ) ;" to complete DoStatement

at StudentMenu.main(StudentMenu.java:104)

What IDE are you using?

It seems like you need to organize your brackets. Pretty much error is saying your while ( expression ) is after the wrong bracket (not at the end of the do statement.).

The error message is incredibly helpful, telling you what exactly is wrong. What do you need from us?

I suggest you indent your code properly. Your indents are currently all over the place and useless. With properly indented source code PLUS the error message. you'll see the source of the error.

Originally Posted by Rend

What IDE are you using?

It seems like you need to organize your brackets. Pretty much error is saying your while ( expression ) is after the wrong bracket (not at the end of the do statement.).

 
 
import java.util.ArrayList;
import java.util.Scanner;
	public class StudentMenu	{
	    public static void main(String[] args)
	    		{
 
	    	ArrayList<Student> studentlist = new ArrayList<Student>();
	        Student nextStudent;
	        int select;
 
 
	        String fName;
	        String sName;
	        String grade;
	        int mark;
 
 
 
	        do	{
	            System.out.println("Please choose and option:[1-4].\n"+
	                    "1 - Add a Student.\n"+
	                    "2 - Delete a Student.\n"+
	                    "3 - List all Students.\n"+
	                    "4 - Exit.");
	            Scanner keyboard = new Scanner(System.in);
	            select=keyboard.nextInt();
 
	            switch(select)
	            	{
 
	            case 1:	   
	            	System.out.print("Please enter no of students ");
                    int numstudents = keyboard.nextInt();
                    keyboard.nextLine();
 
				for (int i=0; i<numstudents; i++)
	                {
	                    System.out.print("Please enter students first name: ");
	                    fName = keyboard.next();
	                    System.out.println();
 
 
	                    System.out.print("Please enter students surname: ");
	                    sName  = keyboard.next();
	                    System.out.println();   
 
	                    System.out.print("Please enter your exam mark: ");
	                    mark  = keyboard.nextInt();
	                    System.out.println();
 
	                    nextStudent = new Student (fName,sName,mark);
	                    studentlist.add(nextStudent);
 
	                }
	                break;
	            case 2:
	            	{
	            		System.out.print("Please enter student you want to delete first name: ");
	            		fName = keyboard.next();
	            		System.out.println();
 
 
	            		System.out.print("Please enter students surname: ");
	            		sName  = keyboard.next();
	            		System.out.println();   
 
               for (Student s: studentlist)
                 	{
 
                    	if	( (s.getFname().equals(fName)) && (s.getSname().equals(sName)))
 
                    			studentlist.remove(s);
                 	}
	            	}
	            	break;
	            case 3:
	            	{
	            for (Student s: studentlist)
	                {
	            		 System.out.println(s);
	                }
	            	}
	            	break;
 
 
	            case 4:
	            	{
	            	 	System.out.println("Goodbye");
	            	}
	            	break;
	            	{	 
	            Default:
	            	{
 
	            	System.out.println("Invalid Selection, Plaese try again");
	            	}
	            	break;
 
	            	}
	            	while (select!=4);
	            	}
 
 
	        		}
	    			}
 
	    			}

Is that better now still cant see my mistake,checked all brackets and also moved the while but it made it worse.

--- Update ---

Originally Posted by GregBrannon

The error message is incredibly helpful, telling you what exactly is wrong. What do you need from us?

I suggest you indent your code properly. Your indents are currently all over the place and useless. With properly indented source code PLUS the error message. you'll see the source of the error.

 
 
import java.util.ArrayList;
import java.util.Scanner;
	public class StudentMenu	{
	    public static void main(String[] args)
	    		{
 
	    	ArrayList<Student> studentlist = new ArrayList<Student>();
	        Student nextStudent;
	        int select;
 
 
	        String fName;
	        String sName;
	        String grade;
	        int mark;
 
 
 
	        do	{
	            System.out.println("Please choose and option:[1-4].\n"+
	                    "1 - Add a Student.\n"+
	                    "2 - Delete a Student.\n"+
	                    "3 - List all Students.\n"+
	                    "4 - Exit.");
	            Scanner keyboard = new Scanner(System.in);
	            select=keyboard.nextInt();
 
	            switch(select)
	            	{
 
	            case 1:	   
	            	System.out.print("Please enter no of students ");
                    int numstudents = keyboard.nextInt();
                    keyboard.nextLine();
 
				for (int i=0; i<numstudents; i++)
	                {
	                    System.out.print("Please enter students first name: ");
	                    fName = keyboard.next();
	                    System.out.println();
 
 
	                    System.out.print("Please enter students surname: ");
	                    sName  = keyboard.next();
	                    System.out.println();   
 
	                    System.out.print("Please enter your exam mark: ");
	                    mark  = keyboard.nextInt();
	                    System.out.println();
 
	                    nextStudent = new Student (fName,sName,mark);
	                    studentlist.add(nextStudent);
 
	                }
	                break;
	            case 2:
	            	{
	            		System.out.print("Please enter student you want to delete first name: ");
	            		fName = keyboard.next();
	            		System.out.println();
 
 
	            		System.out.print("Please enter students surname: ");
	            		sName  = keyboard.next();
	            		System.out.println();   
 
               for (Student s: studentlist)
                 	{
 
                    	if	( (s.getFname().equals(fName)) && (s.getSname().equals(sName)))
 
                    			studentlist.remove(s);
                 	}
	            	}
	            	break;
	            case 3:
	            	{
	            for (Student s: studentlist)
	                {
	            		 System.out.println(s);
	                }
	            	}
	            	break;
 
 
	            case 4:
	            	{
	            	 	System.out.println("Goodbye");
	            	}
	            	break;
	            	{	 
	            Default:
	            	{
 
	            	System.out.println("Invalid Selection, Plaese try again");
	            	}
	            	break;
 
	            	}
	            	while (select!=4);
	            	}
 
 
	        		}
	    			}
 
	    			}

Is that better now still cant see my mistake,checked all brackets and also moved the while but it made it worse.

You're funny. I'm chuckling anyway. You moved the while() statement from after the close brace to below the same close brace. Did you expect that to make a difference?

And you have an odd sense of properly indented code. I've pasted how it would be properly indented in my world. If you don't know how to do this or get help doing this, then ask. (Check out the switch() statement's default block.)

import java.util.ArrayList;
import java.util.Scanner;
 
public class StudentMenu
{
    public static void main ( String[] args )
    {
        ArrayList<Student> studentlist = new ArrayList<Student>();
        Student nextStudent;
        int select;
        String fName;
        String sName;
        String grade;
        int mark;
 
        do
        {
            System.out.println ( "Please choose and option:[1-4].\n" +
                                 "1 - Add a Student.\n" +
                                 "2 - Delete a Student.\n" +
                                 "3 - List all Students.\n" +
                                 "4 - Exit." );
 
            Scanner keyboard = new Scanner ( System.in );
            select = keyboard.nextInt();
 
            switch ( select )
            {
                case 1:
                    System.out.print ( "Please enter no of students " );
                    int numstudents = keyboard.nextInt();
                    keyboard.nextLine();
                    for ( int i = 0; i < numstudents; i++ )
                    {
                        System.out.print ( "Please enter students first name: " );
                        fName = keyboard.next();
                        System.out.println();
                        System.out.print ( "Please enter students surname: " );
                        sName  = keyboard.next();
                        System.out.println();
                        System.out.print ( "Please enter your exam mark: " );
                        mark  = keyboard.nextInt();
                        System.out.println();
                        nextStudent = new Student ( fName, sName, mark );
                        studentlist.add ( nextStudent );
                    }
                break;
 
                case 2:
                {
                    System.out.print ( "Please enter student you want to delete first name: " );
                    fName = keyboard.next();
                    System.out.println();
                    System.out.print ( "Please enter students surname: " );
                    sName  = keyboard.next();
                    System.out.println();
                    for ( Student s : studentlist )
                    {
                        if  ( ( s.getFname().equals ( fName ) ) && ( s.getSname().equals ( sName ) ) )
                        {
                            studentlist.remove ( s );
                        }
                    }
                }
                break;
 
                case 3:
                {
                    for ( Student s : studentlist )
                    {
                        System.out.println ( s );
                    }
                }
                break;
 
                case 4:
                {
                    System.out.println ( "Goodbye" );
                }
                break;
 
                {
                    Default:
                    {
                        System.out.println ( "Invalid Selection, Plaese try again" );
                    }
                    break;
                }
                while ( select != 4 );
            }
        }
 
    } // end method main()
 
} // end class StudentMenu

Edit: Oh, and I would reduce all lines to less than 80 columns.

Sorry ya your right i dont know how to indent the code never did it,this 1 error is driving me around the bend,can you see my mistake because i cant for the life of me.

Find the close brace at the end of the do{} loop and move the while() statement immediately after that brace, same line as the '}', next line, it doesn't matter. The '{' that begins the do loop is underneath the 'do'. The '}' that ends the do{} loop is lined up with the '{' that begins the do{} loop.

What source code editor or IDE are you using?

If you fix the default: clause, the error in while() location should be even more obvious.

The IDE I am using is eclipse,I did what you said but now getting an error with the default case it is unreachable code?

Exception in thread "main" java.lang.Error: Unresolved compilation problem:
Unreachable code

at StudentMenu.main(StudentMenu.java:82)

import java.util.ArrayList;
import java.util.Scanner;
 
public class StudentMenu
{
    public static void main ( String[] args )
    {
        ArrayList<Student> studentlist = new ArrayList<Student>();
        Student nextStudent;
        int select;
        String fName;
        String sName;
        String grade;
        int mark;
 
        do
        {
            System.out.println ( "Please choose and option:[1-4].\n" +
                                 "1 - Add a Student.\n" +
                                 "2 - Delete a Student.\n" +
                                 "3 - List all Students.\n" +
                                 "4 - Exit." );
 
            Scanner keyboard = new Scanner ( System.in );
            select = keyboard.nextInt();
 
            switch ( select )
            {
                case 1:
                    System.out.print ( "Please enter no of students " );
                    int numstudents = keyboard.nextInt();
                    keyboard.nextLine();
                    for ( int i = 0; i < numstudents; i++ )
                    {
                        System.out.print ( "Please enter students first name: " );
                        fName = keyboard.next();
                        System.out.println();
                        System.out.print ( "Please enter students surname: " );
                        sName  = keyboard.next();
                        System.out.println();
                        System.out.print ( "Please enter your exam mark: " );
                        mark  = keyboard.nextInt();
                        System.out.println();
                        nextStudent = new Student ( fName, sName, mark );
                        studentlist.add ( nextStudent );
                    }
                break;
 
                case 2:
                {
                    System.out.print ( "Please enter student you want to delete first name: " );
                    fName = keyboard.next();
                    System.out.println();
                    System.out.print ( "Please enter students surname: " );
                    sName  = keyboard.next();
                    System.out.println();
                    for ( Student s : studentlist )
                    {
                        if  ( ( s.getFname().equals ( fName ) ) && ( s.getSname().equals ( sName ) ) )
                        {
                            studentlist.remove ( s );
                        }
                    }
                }
                break;
 
                case 3:
                {
                    for ( Student s : studentlist )
                    {
                        System.out.println ( s );
                    }
                }
                break;
 
                case 4:
                {
                    System.out.println ( "Goodbye" );
                }
                break;
 
                {
                    Default:
                    {
                        System.out.println ( "Invalid Selection, Plaese try again" );
                    }
                    break;
                }
                while ( select != 4 );
            }
        }
        while ( select != 4 );
 
 
    } // end method main()
 
} // end class StudentMenu

Using Eclipse, there's no reason to post the mess you had originally. To format your code, select all of it, or just a piece of it that you want to format, and select CTRL-i.

To find the end of the the do{} clause, put your cursor next to the open brace, '{', after the 'do', and the ending brace, '}', will be highlighted or somehow identified depending on how you've configured your installation.

No, you didn't do what I said, because I said, "If you fix the default: clause, the error in while() location should be even more obvious." You haven't fixed the default: clause, and there should not be two while() statements. The first one is currently being ignored, because it's an empty while() clause, but still, there shouldn't be two of them.

I dont have any errors now in the code but after it runs I get an error when running it,problem with the scanner and int.

Please choose and option:[1-4].
1 - Add a Student.
2 - Delete a Student.
3 - List all Students.
4 - Exit.
1
Please enter no of students lkmskfn
Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at StudentMenu.main(StudentMenu.java:31)

import java.util.ArrayList;
import java.util.Scanner;
 
public class StudentMenu
{
    public static void main ( String[] args )
    {
        ArrayList<Student> studentlist = new ArrayList<Student>();
        Student nextStudent;
        int select;
        String fName;
        String sName;
        String grade;
        int mark;
 
        do
        {
            System.out.println ( "Please choose and option:[1-4].\n" +
                                 "1 - Add a Student.\n" +
                                 "2 - Delete a Student.\n" +
                                 "3 - List all Students.\n" +
                                 "4 - Exit." );
 
            Scanner keyboard = new Scanner ( System.in );
            select = keyboard.nextInt();
 
            switch ( select )
            {
                case 1:
                    System.out.print ( "Please enter no of students " );
                    int numstudents = keyboard.nextInt();
                    keyboard.nextLine();
                    for ( int i = 0; i < numstudents; i++ )
                    {
                        System.out.print ( "Please enter students first name: " );
                        fName = keyboard.nextLine();
                        System.out.println();
                        System.out.print ( "Please enter students surname: " );
                        sName  = keyboard.nextLine();
                        System.out.println();
                        System.out.print ( "Please enter your exam mark: " );
                        mark  = keyboard.nextInt();
                        System.out.println();
                        nextStudent = new Student ( fName, sName, mark );
                        studentlist.add ( nextStudent );
                    }
                break;
 
 
                case 2:
                {
                    System.out.print ( "Please enter student you want to delete first name: " );
                    fName = keyboard.next();
                    System.out.println();
                    System.out.print ( "Please enter students surname: " );
                    sName  = keyboard.next();
                    System.out.println();
                    for ( Student s : studentlist )
                    {
                        if  ( ( s.getFname().equals ( fName ) ) && ( s.getSname().equals ( sName ) ) )
                        {
                            studentlist.remove ( s );
                        }
                    }
                }
                break;
 
                case 3:
                {
                    for ( Student s : studentlist )
                    {
                        System.out.println ( s );
                    }
                }
                break;
 
                case 4:
                {
                    System.out.println ( "Goodbye" );
                }
 
 
                {
                    Default:
                    {
                        System.out.println ( "Invalid Selection, Plaese try again" );
                    }
                    break;
                }
 
            }
        }
        while ( select != 4 );
 
 
    } // end method main()
 
} // end class StudentMenu