سؤال حول الاستفادة من الاستثناءات في اعادة تنفيذ Step ما

لعلي أكون قد فهمت ما تقصد .. هل هذا ما تريده :

String st =  JOptionPane.showInputDialog ("Enter a number");
boolean done = false;
while(!done)
{
try
{
	 int ist = Integer.parseInt (st);
	done = true;
} catch (Exception e) {
	 System.out.println ("Exception detected, exception message: " + e);
	  // done = false;
}
}// while

نسيت!

صحيح ;)

يسلمو ايديك يا باشا, تمت الإجابة :)

بارك الله فيك أخي الشمري -سبقتني إلى نفس الفكرة :) -

الآن وبعد انتهاء الوقت المخصص لتسليم الوظيفة أطرحها لعل أحداً ما يستفيد منها في يوم من الأيام (رغم أنها متواضعة وبسيطة :blush:)

// برنامج لقراءة مصفوفتين, اسماء طلاب وعلاماتهم
// طباعة العلامات والاسماء في جدول
// الترتيب والطباعة تنازليا حسب العلامات
// الترتيب والطباعة تصاعديا حسب الاسماء
// اظهار اعلى علامة لطالب في القسم
// اظهار علامات واسماء الطلاب الراسبين
// a program to store students names and marks
// then print out some specific information about the process
import javax.swing.JOptionPane;

public class hm02
{
	// declare public vars
	static int istNumber;
	static String[] names; // array of strings for students names
	static int[] marks; // array of integers for students marks
	static String stNumber;

	public static void main (String[] args)
	{
		// call a subroutine to receive students numbers to enter
		ReadInteger();
		// call a subroutine to receive students names
		ReadNames();
		// call a subroutine to receives students marks
		ReadMarks();
		// call a subroutine to print students names and marks in a table
		System.out.println ("You have entered the following inforamtion:");
		PrintTable();
		// call a subroutine to sort students table by marks descending and print the table
		SortIntArray();
		System.out.println ("Students table information arranged in descending order by mark:");
		PrintTable();
		// call a subroutine to sort students table by names ascending and print the table
		SortNamesArray();
		System.out.println ("Students table information arranged in ascending order by name:");
		PrintTable();

		SortIntArray();
		// print out first student on class, the student with highest mark & ofcourse who has mark +60
		if (marks[0] > 59)
		{
			System.out.println (names[0] + " is first on class with total of " + marks[0] + " marks.\n");
		} else {
			System.out.println ("None is first on class because no one has passed!\n");
		}

		System.out.println ("Students that failed:");
		int j = 0;
		// search the table for marks less than 60 and print them as failed students
		for (int i = 0; i <= istNumber-1; i++)
		{
			if (marks < 60)
			{
				j += 1;
				System.out.println (" " + j + ". " + names + " with total of " + marks + " marks."); // print out failed students names with marks
			}
		}
	}

	// fault detection subroutine
	static String isEmpty(String num, String msg)
	{
		if (num == null || num.trim().length() == 0)
		{
			do // repeat
			{
				num = JOptionPane.showInputDialog ("Invalid input; " + msg);
			} while (num == null || num.trim().length() == 0); // as long as input is invalid
		}
		return num;
	}

	static void ReadInteger()
	{
		boolean done = false;
		while (!done)
		{
			try
			{
				// receive students number from user.
				stNumber = JOptionPane.showInputDialog ("How many students do you want to enter?");

				// check if input is empty or has been cancelled by user
				stNumber = isEmpty(stNumber, "How many students do you want to enter"); // passes a special msg to display for each fault

				// convert input from String to Integer, using structered exception handler to detect invalid char input
				istNumber = Integer.parseInt (stNumber);
				done = true;
			} catch (Exception e) { // catch exception if it detects invalid char during conversion
				// prints out neat and clear message to inform user with the exception type.
				System.out.println ("Exception occured, possible reason: invalid input, suggest: use numbers only");
				System.out.println ("Exception message: " + e + "\n\n");
			} finally {
				// check if number is within the valid range for Integer types
				if (done == true && istNumber <= 0 || istNumber > 65535)
				{
					System.out.println ("Valid numbers range is [1 - 65535]\n\n"); // inform the user with valid range
					done = false;
				}
			}
		}

		// inform the user with the number he has given
		System.out.println ("You want to enter " + istNumber + " students inforamtion\n\n");
	}

	static void ReadNames()
	{
		names = new String [istNumber]; // declare an array of strings with length specified by number of students
		for (int i = 0; i <= istNumber-1; i++)
		{
			names = JOptionPane.showInputDialog ("Student number " + (i+1) + " name is?"); // ask the user to enter a student name
			names = isEmpty(names, "Student number " + (i+1) + " name is?"); // check if the given value is empty or null
		}
		// finished filling all students names, return
	}

	static void ReadMarks()
	{
		marks = new int [istNumber]; // declare an array of integers with length specified by number of students
		for (int i = 0; i <= istNumber-1; i++)
		{
			boolean done = false;
			while (!done)
			{
				String m = JOptionPane.showInputDialog (names + " mark is?"); // ask the user to enter a student mark
				m = isEmpty(m, names + " mark is?"); // check if the given value is empty or null
				try { // use exception handling to decide if the given value is an integer or contains invalid chars
					marks = Integer.parseInt (m);
					done = true;
				} catch (Exception e) { // catch exception if it detects invalid char during conversion
					// prints out neat and clear message to inform user with the exception type.
					System.out.println ("Exception occured, possible reason: invalid input, suggest: use numbers only");
					System.out.println ("Exception message: " + e + "\n\n");
				} finally {
					if (done == true && marks < 0 || marks > 100) // check if mark is a negative number, or over 100
					{
						System.out.println ("Student can't have a negative mark or mark over 100!\n");
						done = false;
					}
				}
			}
		}
	}

	static void PrintTable()
	{
		// print out table header
		System.out.println ("|		Student Name			|		Student Mark		|");
		System.out.println ("============================================================================
=");
		// enter a loop to print all students names & marks
		for (int i = 0; i <= istNumber-1; i++)
		{
			System.out.print (" " + (i+1) + ". "); // print a preceeding number for student
			System.out.print (names); // print student name
			for (int j = 0; j <= (35-names.length()); j++) // decide how many spaces to print after student name to fit the table column width;)
			{
				System.out.print (" "); // add trailing spaces
			}
			System.out.println ("				  " + marks); // print student mark exactly where we want it to appear, middle of the student mark column
		}
		System.out.println ("\n\n"); // add 2 line breaks for best view
	}

	static void SortIntArray()
	{
		// declare some vars
		int m;
		String n;
		for (int i = 0; i <= istNumber-1; i++) // index  first element in the marks array
		{
			for (int j = i+1; j <= istNumber-1; j++) // value to compare to as index+1 in marks array
			{
				// assume marks is maximum mark, compare it with the following array element
				if (marks < marks[j]) // check if the following element is higher
				{
					// swap between two values, put highest value on first array element to comapre it with all the array elements left
					m = marks; // save it
					marks = marks[j]; // move highest value to lowest value space
					marks[j] = m; // restore lowest value to highest value old space
					n = names; // do the same with students names to match their marks
					names = names[j];
					names[j] = n;
				}
			}
		}
	}

	static void SortNamesArray()
	{
		// declare some vars
		int s, m;
		String n;
		for (int i = 0; i <= istNumber-1; i++) // a bulk loop to go over all array elements.
		{
			for (int j = 1; j <= names.length-1; j++) // index second element in the names array
			{
				s = names[j].compareTo(names[j-1]); // compare index value with previous array element value;e.g: index with index-1
				if (s < 0)
				{
					// swap between names in the array
					m = marks[j]; // save it
					marks [j] = marks[j-1]; // move name at index-1 to index
					marks[j-1] = m; // restore saved name to index-1
					n = names[j]; // do the same with students marks to match their names
					names[j] = names[j-1];
					names[j-1] = n;
				}
			}
		}
	}
}