Java 我如何做这个if语句？

为这个愚蠢的问题道歉，我目前正在努力学习java。我需要此代码才能工作，这样它就会重复，除非为studentNumber输入了“0”。当我必须在if语句之前声明int时，我不确定如何使“please enter student number”部分工作？我不确定我是否完全错了，但我需要能够重复数据输入，除非输入“0”作为studentNumber。谢谢你的帮助

class Main { 
    public static void main( String args[] ) {
        int studentNumber = BIO.getInt();

        if(studentNumber > 0) {
            System.out.print("#Please enter the student number : ");

            System.out.print("#Please enter the coursework mark : ");
            int courseWork = BIO.getInt();

            System.out.print("#Please enter the exam mark : ");
            int examMark = BIO.getInt();

            double average = (double)(courseWork + examMark) / 2;

            System.out.printf("sn = " + studentNumber
                    + " ex = " + examMark + " cw = " + courseWork 
                    + " mark = " + average);
            } else {
                System.out.print("#End of data");
            }
        }
    }
}

使用while（）

另见

使用

while（）

另见

---

您应该使用

while

语句，并执行以下操作：

class Main
    { 
        public static void main( String args[] )
        {
                int studentNumber = 1;
                While(studentNumber > 0)
                {
                studentNumber = BIO.getInt();

                System.out.print("#Please enter the student number : ");


                System.out.print("#Please enter the coursework mark : ");
                int courseWork = BIO.getInt();

                System.out.print("#Please enter the exam mark : ");
                int examMark = BIO.getInt();

                double average = (double)(courseWork + examMark) / 2;

                System.out.printf("sn = " + studentNumber + " ex = " + examMark + " cw = " + courseWork + " mark = " + average);
              }

                else
              {
                  System.out.print("#End of data");

              }
        }
    }

---

您应该使用

while

语句并执行以下操作：

class Main
    { 
        public static void main( String args[] )
        {
                int studentNumber = 1;
                While(studentNumber > 0)
                {
                studentNumber = BIO.getInt();

                System.out.print("#Please enter the student number : ");


                System.out.print("#Please enter the coursework mark : ");
                int courseWork = BIO.getInt();

                System.out.print("#Please enter the exam mark : ");
                int examMark = BIO.getInt();

                double average = (double)(courseWork + examMark) / 2;

                System.out.printf("sn = " + studentNumber + " ex = " + examMark + " cw = " + courseWork + " mark = " + average);
              }

                else
              {
                  System.out.print("#End of data");

              }
        }
    }

使用

while（）

代替

if

，并进行以下更改：

System.out.print("#Please enter the student number : ");
int studentNumber = BIO.getInt();

while(studentNumber > 0) {
    System.out.print("#Please enter the coursework mark : ");
    int courseWork = BIO.getInt();

    System.out.print("#Please enter the exam mark : ");
    int examMark = BIO.getInt();

    double average = (double)(courseWork + examMark) / 2;
    System.out.printf("sn = " + studentNumber
            + " ex = " + examMark + " cw = " + courseWork 
            + " mark = " + average);

    System.out.print("#Please enter the student number : ");
    studentNumber = BIO.getInt();
} 

System.out.print("#End of data");

与其他答案相反，这将确保即使在第一次迭代中，您也会执行检查（并提示用户输入学号）。

使用

while（）

而不是

if

，并进行以下更改：

System.out.print("#Please enter the student number : ");
int studentNumber = BIO.getInt();

while(studentNumber > 0) {
    System.out.print("#Please enter the coursework mark : ");
    int courseWork = BIO.getInt();

    System.out.print("#Please enter the exam mark : ");
    int examMark = BIO.getInt();

    double average = (double)(courseWork + examMark) / 2;
    System.out.printf("sn = " + studentNumber
            + " ex = " + examMark + " cw = " + courseWork 
            + " mark = " + average);

    System.out.print("#Please enter the student number : ");
    studentNumber = BIO.getInt();
} 

System.out.print("#End of data");

与其他答案相反，这将确保即使在第一次迭代中，您也会执行检查（并提示用户输入学号）。

使用从用户处获取输入并处理输入值

import java.util.Scanner;

public class ConditionCheck {
    public static void main(String[] args) {
       Scanner BIO = new Scanner(System.in);

       System.out.print("#Please enter the student number : ");
       int studentNumber = BIO.nextInt();

       if(studentNumber > 0) {
        System.out.print("#Please enter the coursework mark : ");
        int courseWork = BIO.nextInt();

        System.out.print("#Please enter the exam mark : ");
        int examMark = BIO.nextInt();

        double average = (double)(courseWork + examMark) / 2;
        System.out.printf("sn = " + studentNumber
                + " ex = " + examMark + " cw = " + courseWork 
                + " mark = " + average);
        } else {
            System.out.print("#End of data");
        }
   }

}

用于从用户处获取输入并处理输入值

import java.util.Scanner;

public class ConditionCheck {
    public static void main(String[] args) {
       Scanner BIO = new Scanner(System.in);

       System.out.print("#Please enter the student number : ");
       int studentNumber = BIO.nextInt();

       if(studentNumber > 0) {
        System.out.print("#Please enter the coursework mark : ");
        int courseWork = BIO.nextInt();

        System.out.print("#Please enter the exam mark : ");
        int examMark = BIO.nextInt();

        double average = (double)(courseWork + examMark) / 2;
        System.out.printf("sn = " + studentNumber
                + " ex = " + examMark + " cw = " + courseWork 
                + " mark = " + average);
        } else {
            System.out.print("#End of data");
        }
   }

}

---

我应该使用while语句还是其他什么？在移动提示符（

print（“#请输入学生编号：”）

）的同时切换if。我应该使用while语句还是其他什么？在移动提示符（

print（“#请输入学生编号：”）

）的同时切换if如果我这样做，它说变量已经定义（studentNumber）@Austin对不起，我更新了：）现在应该可以工作了我很高兴它帮助了你如果我这样做，它说变量已经定义（studentNumber）@Austin我很抱歉，我更新了：）现在应该可以工作了我很高兴它帮助了你