Exception in thread "main" java.lang.NullPointerException: 哪里出了问题(๑•́ ₃ •̀๑)

Question

import java.util.Scanner;
//定义主类
public class TestStudent {
public static void main (String[] args) {

Student Stu = new Student();
Stu.Input();


}

}

//定义类
class Student {
String[] name;
char[] sex;
float[] math;
float[] daishu;
float[] C;
float[] object;
int n;
public void Input () {
Scanner sc = new Scanner(System.in);
System.out.println("请输入录入学生数量:");
n = sc.nextInt();
for(int i = 1;i<=n;i++) {
System.out.println("请输入第"+i+"组数据");

    System.out.println("请输入第"+i+"组姓名");
    name[i] = sc.nextLine();
    System.out.println("请输入第"+i+"组性别");
    sex[i] = sc.next().charAt(0);
    System.out.println("请输入第"+i+"组高数成绩");
    math[i] = sc.nextFloat();
    System.out.println("请输入第"+i+"组线性代数成绩");
    daishu[i] = sc.nextFloat();
    System.out.println("请输入第"+i+"组C语言成绩");
    C[i] = sc.nextFloat();
    System.out.println("请输入第"+i+"组面向对象成绩");
    object[i] = sc.nextFloat();
    }
}

}

Answer 1

因为你的属性都只创建了类似指针的对象,但是没有分配对应地址
在input接受输入后对应分配空间即可

     Scanner sc = new Scanner(System.in);
        System.out.println("请输入录入学生数量:");
        n = sc.nextInt();
        name = new String[n];
        sex = new char[n];
        math = new float[n];
        daishu = new float[n];
        C = new float[n];
        object = new float[n];