java - 嵌套控制结构，平均脚本

Question

使用嵌套控制结构编写脚本，对 0 到 100 之间的任何数字进行平均，如果任何数字高于 100 或低于 0，则会产生错误。

import java.util.Scanner;

public class ExerciseSix
{
public static void main( String[] args )
{

    Scanner dylan = new Scanner(System.in);

    int gradeCounter;
    int total;
    int grade;
    double average;

    total = 0;
    gradeCounter = 0;

    System.out.println( "Enter a grade or -1 to quit: " );
    grade = dylan.nextInt();

    while ( grade != -1 )
    {

        total = total + grade;
        gradeCounter = gradeCounter + 1;





        System.out.println( "Enter grade or -1 to quit: ");
        grade = dylan.nextInt();


        if ( grade > 100 );
        System.out.println( "Number too large");            

        if ( grade < 0 );
        System.out.println( "Number too small");
    }


    if ( gradeCounter != 0 )

    {

        average = (double) total / gradeCounter;


        System.out.printf( "Class average is %.2f", average );



    }

    else
        System.out.println( "No grades were entered" );

}

我没有收到任何编译错误，但是当我输入数字时，第一个数字会正确输入。然后无论我输入 0 到 100 之间的哪个数字，它都会显示

“5 数量太大 数量太小 输入成绩或 -1 退出:“

我认为大量数字也被添加到平均值中

Answer 1

删除 if 语句中的分号

改变

if ( grade > 100 );
    System.out.println( "Number too large");            

if ( grade < 0 );
    System.out.println( "Number too small");

到

if ( grade > 100 )
    System.out.println( "Number too large");            

if ( grade < 0 )
    System.out.println( "Number too small");

最佳实践是将所有 if 语句用大括号括起来，这样就不会出现任何意外行为

if ( grade > 100 ){
    System.out.println( "Number too large");  
}          

对于要添加到总数中的大数字，您需要在计算之前进行数据验证，即

while(grade != -1){
    if( grade > 100 || grade < 0) {
    //Message
    }
    else{
    //Total calculation
    }
}