建议：

• 如果你想要一个更快的答案，分享一个可运行的代码。
• 总是修改你的代码，它会更容易阅读。
• 变量的名称非常重要，所以请给予一个合适的名称，以了解它们包含的内容。（例如，您声明了一个变量“total”，它将包含平均结果，将其称为“avg”或“average”是合理的）

这是一个测试类：

class StackOverflowTest {

    // regex pattern
    private static final String REGEX_Y_OR_N = "^[yn]$";
    
    @Test
    void execute() {
        
        Scanner scan = new Scanner(System.in);
        
        String needToContinue = "x";
        
        // loop until the user press "n"
        do {
            
            // for each iteration, tot and count will be reinitialized
            int tot = 0;
            int count = 0;
            
            // loop until the user enter 5 numbers
            do {
                
                System.out.print("Enter a number : ");
                
                int input;
                if (scan.hasNextInt()) {
                    input = scan.nextInt();
                    count++;
                } else {
                    System.out.println("Number is invalid."+"\n");
                    scan.next();
                    continue;
                }
                
                tot += input;

            } while (count < 5);

            double avg = tot / 5;

            System.out.println("The average is : " + avg + " .");

            System.out.println("\n"+" [do you want to continue press [ y ] for yes and [ n ] for no ]: ");
            
            // loop until a valid character is entered ("y" or "n")
            do {
                
                needToContinue = scan.next();
                
                if (!needToContinue.matches(REGEX_Y_OR_N)) {
                    System.out.println("\n"+"Invalid character!"+"\n");
                    System.out.println(" [do you want to continue press [ y ] for yes and [ n ] for no ]: ");
                }
                
            } while (!needToContinue.matches(REGEX_Y_OR_N)); 
            

        } while (needToContinue.contains("y"));
        
        scan.close();
    }
    
}

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