Daily practice ----- there is a group of students' grades. Arrange them in descending order. To add a student's grade, insert it into the grade sequence and keep the descending order

  subject : There is a group of students' achievements {99,82,85,60, 63}, Arrange them in descending order . To increase the performance of a student , Insert it into the grade sequence , And keep descending

The key to solving the problem is :  Descending order , After increasing students' scores, they still need to be arranged in descending order

Ideas : 1) First arrange the original array in descending order
          2) Create a new array that is longer than the original array 1 Array of  
          3) Store the elements in the original array in order in the new array
          4) Use Scanner Get the student grades you want to increase
          5) Through cyclic comparison , Get the position where the inserted element is to be inserted ( Subscript )
          6) The elements starting from and after the insertion position move one bit back ( Be careful : When moving , Move forward from behind )
          7) After moving the element , The insertion position is empty , Store the inserted element in the insertion location
 

The process :  Next, we write code step by step according to our problem-solving ideas

         // Output the array required by the topic

         int[] scores = { 99, 82, 80, 60, 63 };

        //1) First arrange the original array in descending order

        for (int i = 0; i < scores.length; i++) {
            for (int j = i + 1; j < scores.length; j++) {
                if (scores[i] < scores[j]) {
                    int temp = scores[i];
                    scores[i] = scores[j];
                    scores[j] = temp;
                    break;
                }
            }
        }

        // Traversal array , See if it succeeds in descending order

        System.out.println(" The descending array is :");

        for (int i = 0; i < scores.length; i++) {
            System.out.print(scores[i] + " ");
        }

        

        

         //2) Create a new array that is longer than the original array 1 Array of  

        int[] newScores = new int[scores.length + 1];

        // 3) Store the elements in the original array in order in the new array
                for (int i = 0; i < scores.length; i++) {
                    newScores[i] = scores[i];
                }
                System.out.println();

                // 4) Use Scanner Get the student grades you want to increase
                Scanner sc = new Scanner(System.in);
                System.out.println(" Please enter the increased student grade ");
                int insert = sc.nextInt();

                // 5) Through cyclic comparison , Get the position where the inserted element is to be inserted ( Subscript )

                int index = newScores.length - 1; // Prevent mistakes when the score is negative
                for (int i = 0; i < newScores.length; i++) {
                    if (insert > newScores[i]) {
                        index = i;
                        // Once the inserted element is larger than a certain element , No further comparison
                        break;
                    }
                }

                // 6) The elements starting from and after the insertion position move one bit back ( Be careful : When moving , Move forward from behind )
                for (int i = newScores.length - 1; i > index; i--) {
                    newScores[i] = newScores[i - 1];
                }

                // 7) After moving the element , The insertion position is empty , Store the inserted element in the insertion location
                newScores[index] = insert;

                // After inserting the element , Traverse the new array

                System.out.println(" The new array in descending order after inserting grades is :");
                for  (int j = 0; j < newScores.length; j++) {
                           System.out.print(newScores[j] + " ");
                }

        The complete results are as follows :

  summary :

         This program mainly uses the knowledge of array loops , Part of the program is " int index = newScores.length - 1;" If written "int index = 0", And the inserted score is negative , Then the following results will appear :

So the assignment of this requires extra attention .

For the convenience of everyone , The source code is attached below :

int[] scores = { 99, 85, 63, 60, 82 };

		//1) First arrange the original array in descending order 
		for (int i = 0; i < scores.length; i++) {
			for (int j = i + 1; j < scores.length; j++) {
				if (scores[i] < scores[j]) {
					int temp = scores[i];
					scores[i] = scores[j];
					scores[j] = temp;
					break;
				}
			}
		}
		// Output the descending array 
		System.out.println(" The descending array is :");
		for (int i = 0; i < scores.length; i++) {
			System.out.print(scores[i] + " ");
		}

		// 2) Create a new array that is longer than the original array 1 Array of 
		int[] newScores = new int[scores.length + 1];

		// 3) Store the elements in the original array in order in the new array 
		for (int i = 0; i < scores.length; i++) {
			newScores[i] = scores[i];
		}
		System.out.println();

		// 4) Use Scanner Get the student grades you want to increase 
		Scanner sc = new Scanner(System.in);
		System.out.println(" Please enter the increased student grade ");
		int insert = sc.nextInt();

		// 5) Through cyclic comparison , Get the position where the inserted element is to be inserted ( Subscript )
		int index = 0;
		for (int i = 0; i < newScores.length; i++) {
			if (insert > newScores[i]) {
				index = i;
				//  Once the inserted element is larger than a certain element , No further comparison 
				break;
			}
		}

		// 6) The elements starting from and after the insertion position move one bit back ( Be careful : When moving , Move forward from behind )
		for (int i = newScores.length - 1; i > index; i--) {
			newScores[i] = newScores[i - 1];
		}

		// 7) After moving the element , The insertion position is empty , Store the inserted element in the insertion location 
		newScores[index] = insert;

		//  After inserting the element , Traverse the new array 
		System.out.println(" The new array in descending order after inserting grades is :");
		for (int j = 0; j < newScores.length; j++) {
			System.out.print(newScores[j] + " ");
		}

Practice tomorrow : Realize the lottery function of two-color ball . The rules ： from 36 Randomly choose the non repeating one among the red balls 6 Number , from 15 Randomly choose from basketball 1 Make up a lottery . You can choose to buy more notes .

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