无法在循环中正常工作-java

Question

我的问题是，当我运行这个程序时，我必须按 2 两次或 3 次才能运行 else if 语句。我尝试将输入切换为字符串，它也有同样的问题。 (you can ignore all the code except the (sc.nextInt()==1)/(sc.nextInt()==2)/(sc.nextInt()==3)) 这些是我遇到问题的地方。谢谢

 Scanner sc = new Scanner(System.in);
            int running = 0;
            do
            {
                System.out.println("What would you like to do?");
                System.out.println("(1)Enter hourly employee");
                System.out.println("(2)Enter commissionary employee");
                System.out.println("(3)Terminate program");
                System.out.println();
                if (sc.nextInt()==1){
                    System.out.println("Enter their first name. \n");
                    hour.firstName= sc.next();
                    System.out.println("Enter their last name. \n");
                    hour.lastName= sc.next();
                    System.out.println("Enter their Id #. \n");
                    hour.id= sc.nextInt();
                    System.out.println("Enter their wage amount. \n");
                    hour.wage= sc.nextInt();
                    System.out.println("Enter how many hours they will be working. \n");
                    hour.hrs= sc.nextInt();
                    System.out.println("employee "+ hour.id + "'s name is " + hour.firstName + " "+ hour.lastName + " their id is "+ hour.id);
                    System.out.println("employee "+ hour.id + "'s wage is " + hour.wage + "$ and will be working "+ hour.hrs +" hours per week.");
                    running++;

                }

                //have to type 2 twice here
                 else if (sc.nextInt()== 2){
                    System.out.println("Enter their first name. \n");
                    com.firstName= sc.next();
                    System.out.println("Enter their last name. \n");
                    com.lastName= sc.next();
                    System.out.println("Enter their Id #. \n");
                    com.id= sc.nextInt();
                    System.out.println("Enter their base salary. \n");
                    bcom.baseSalary= sc.nextInt();
                    System.out.println("Enter their wage commission rate. \n");
                    com.cRate= sc.nextInt();
                    System.out.println("Enter their expected gross sales goal. \n");
                    com.gSales= sc.nextInt();
                    System.out.println("employee "+ com.id + "'s name is " + com.firstName + " "+ com.lastName + " their id is "+ com.id);
                    System.out.println("employee "+ com.id + "'s base salary is "+ bcom.baseSalary + "$ their commission rate is \n" + com.cRate + "% and is estimated to make "+ com.gSales +"$ in gross sales.");
                    running++;

                }
                //have to type 3 three times here
                else if (sc.nextInt()== 3)
                {
                    running++;
                }


            }while(running < 1);

Answer 1

 Scanner sc = new Scanner(System.in);
            int running = 0;
            do
            {
                System.out.println("What would you like to do?");
                System.out.println("(1)Enter hourly employee");
                System.out.println("(2)Enter commissionary employee");
                System.out.println("(3)Terminate program");
                System.out.println();
                int i = sc.nextInt();
                if (i==1){
                    System.out.println("Enter their first name. \n");
                    hour.firstName= sc.next();
                    System.out.println("Enter their last name. \n");
                    hour.lastName= sc.next();
                    System.out.println("Enter their Id #. \n");
                    hour.id= sc.nextInt();
                    System.out.println("Enter their wage amount. \n");
                    hour.wage= sc.nextInt();
                    System.out.println("Enter how many hours they will be working. \n");
                    hour.hrs= sc.nextInt();
                    System.out.println("employee "+ hour.id + "'s name is " + hour.firstName + " "+ hour.lastName + " their id is "+ hour.id);
                    System.out.println("employee "+ hour.id + "'s wage is " + hour.wage + "$ and will be working "+ hour.hrs +" hours per week.");
                    running++;

                }

                //have to type 2 twice here
                 else if (i== 2){
                    System.out.println("Enter their first name. \n");
                    com.firstName= sc.next();
                    System.out.println("Enter their last name. \n");
                    com.lastName= sc.next();
                    System.out.println("Enter their Id #. \n");
                    com.id= sc.nextInt();
                    System.out.println("Enter their base salary. \n");
                    bcom.baseSalary= sc.nextInt();
                    System.out.println("Enter their wage commission rate. \n");
                    com.cRate= sc.nextInt();
                    System.out.println("Enter their expected gross sales goal. \n");
                    com.gSales= sc.nextInt();
                    System.out.println("employee "+ com.id + "'s name is " + com.firstName + " "+ com.lastName + " their id is "+ com.id);
                    System.out.println("employee "+ com.id + "'s base salary is "+ bcom.baseSalary + "$ their commission rate is \n" + com.cRate + "% and is estimated to make "+ com.gSales +"$ in gross sales.");
                    running++;

                }
                //have to type 3 three times here
                else if (i== 3)
                {
                    running++;
                }


            }while(running < 1);

因为每次你写nextInt()，它都会等待来自用户的输入。因此，只需尝试从用户那里获取 1 个输入，然后检查输入是什么。

Answer 2

您正在从“其他”中的 sc.nextInt() 中第二次阅读。 在“if”之前读取一次，然后测试该值。

Answer 3

每当您调用nextInt() 时，该进程都会等待并读取您的输入一次。

所以，第一个if(sc.nextInt()==1) 读取您的输入一次，您需要输入第二次才能到达else if (sc.nextInt()==2)。

要解决这个问题，请尝试以下结构：

int input = sc.nextInt();
if (input == 1) {
} else if (input == 2) {
} else if (input == 3) {
}