用户输入的总和，平均，最低和最高得分（条件控制结构）

Question

I have the following homework assignment. Our teacher hasn't taught us well, so I need extra help.

Write a Java program that will input five scores of a student in five quizzes. Output the sum and average of five scores. Determine and display the highest and lowest score.

This is how I am stuck now. I only have up to Q3 last time and it only shows the average and the lowest score with no highest score. Kindly help me make this work!

import java.util.Scanner;
import java.io.*;

class Quizzes
{

    public static void main(String[] args) {
    int Q1, Q2, Q3, Q4, Q5;
    double average;

    Scanner keyboard = new Scanner(System.in);
    System.out.print("Enter Quizzes: ");
    Q1 = keyboard.nextInt();
    Q2 = keyboard.nextInt();
    Q3 = keyboard.nextInt();
    Q4 = keyboard.nextInt();
    Q5 = keyboard.nextInt();

    average = (Q1 + Q2 + Q3 + Q4 + Q5) / 5;
    System.out.println("Average Score is: " + average);

    if (Q1 < Q2 && Q1 < Q3) {
        System.out.println("The lowest score is: " + Q1);
    } else if (Q2 < Q1 && Q2 < Q3) {
        System.out.println("The lowest score is: " + Q2);
    } else if (Q3 < Q1 && Q2 < Q3) {
        System.out.println("The lowest score is: " + Q3);
    } else if (Q1 > Q2 && Q1 > Q3) {
        System.out.println("The highest score is: " + Q1);
    } else if (Q2 > Q1 && Q2 > Q3) {
        System.out.println("The highest score is: " + Q2);        
    } else if (Q3 > Q3 && Q1 > Q2) {
        System.out.println("The highest score is: " + Q3);
    } else {
        System.out.println("The lowest score is: " + Q3);
    }

  }
}

Answer 1

In your current solution you have a couple of basic issues such as else if (Q3 > Q3) .

You also don't check for equality ie if (Q2 >= Q3) .

The major issue with your current technique is that you have a load of if/else statements, a better solution would be to use an Array like below:

public class Quizzes {

    public static void main(String[] args) {

        double Q1, Q2, Q3, Q4, Q5;
        double average = 0;
        double max = 0;
        double count = 0;
        double[] userInput = new double[5];

        Scanner keyboard = new Scanner(System.in);
        System.out.print("Enter Quizzes: ");
        System.out.println("");
        Q1 = keyboard.nextInt();
        userInput[0] = Q1;
        Q2 = keyboard.nextInt();
        userInput[1] = Q2;
        Q3 = keyboard.nextInt();
        userInput[2] = Q3;
        Q4 = keyboard.nextInt();
        userInput[3] = Q4;
        Q5 = keyboard.nextInt();
        userInput[4] = Q5;
        keyboard.close();

        for (int i = 0; i < userInput.length; i++) {
            count = count + userInput[i];
            average = count / 5;
        }
        System.out.println("Average Score is: " + average);
        Arrays.sort(userInput);
        System.out.println("The lowest score is: " + userInput[0]);
        max = userInput[userInput.length - 1];
        System.out.println("The highest score is: " + max);
    }

}

EDIT:

Now that you have informed us you cannot use an Array then below code will do the job without modifying your original method too much:

public class Quizzes {

    public static void main(String[] args) {

        double Q1, Q2, Q3, Q4, Q5;
        double average = 0;
        double lowest = 0;

        Scanner keyboard = new Scanner(System.in);
        System.out.print("Enter Quizzes: ");
        System.out.println("");
        Q1 = keyboard.nextDouble();
        Q2 = keyboard.nextDouble();
        Q3 = keyboard.nextDouble();
        Q4 = keyboard.nextDouble();
        Q5 = keyboard.nextDouble();
        keyboard.close();

        average = (Q1 + Q2 + Q3 + Q4 + Q5) / 5;
        System.out.println("Average Score is: " + average);

        if (Q1 <= Q2 && Q1 <= Q3 && Q1 <= Q4 && Q1 <= Q5) {
            lowest = Q1;
        } else if (Q2 <= Q1 && Q2 <= Q3 && Q2 <= Q4 && Q2 <= Q5) {
            lowest = Q2;
        } else if (Q3 <= Q1 && Q3 <= Q2 && Q3 <= Q4 && Q3 <= Q5) {
            lowest = Q3;
        } else if (Q4 <= Q1 && Q4 <= Q2 && Q4 <= Q3 && Q4 <= Q5) {
            lowest = Q4;
        } else if (Q5 <= Q1 && Q5 <= Q2 && Q5 <= Q3 && Q5 <= Q4) {
            lowest = Q5;
        }

        System.out.println("The lowest score is: " + lowest);
        // THEN DO SIMILAR TO GET HIGHEST SCORE
    }
}

Answer 2

You can also insert these values into an array, go over this array and look for the min and max values.

Like this:

int[] arr = new int[5];
arr[0] = Q1;
arr[1] = Q2;
arr[2] = Q3;
arr[3] = Q4;
arr[4] = Q5;


int min = Integer.MAX_VALUE;
int max = Integer.MIN_VALUE;

for (int i=0; i<arr.length; i++){

    min = Math.min(min, arr[i]);
    max = Math.min(max, arr[i]);

}

Answer 3

If you're not allowed to use arrays and/or loops, here's one way to do it. You can see why arrays make it more concise; you would not want to do this for 100 questions. I have left out computation of the maximum, since it's trivially similar.

int min = Integer.MAX_VALUE;
if (Q1 < min) {
    min = Q1;
}
if (Q2 < min) {
    min = Q2;
}
if (Q3 < min) {
    min = Q3;
}
if (Q4 < min) {
    min = Q4;
}
if (Q5 < min) {
    min = Q5;
}