package StudentDemo;

import java.util.*;

public class StudentDemo
{
    static Graduate G[]=null;
    static Student S[]=null;
    static Undergraduate Ug[]=null;

    public static void main(String args[])
    {
        
        String name,sex;
        int sno,mathGreade,EnglishGreade,chinaGreade;
        Scanner x =new Scanner(System.in);
        System.out.println("请输入人数");
        int k=x.nextInt();
        Undergraduate Ug[] = new Undergraduate[k];
        Graduate G[] = new Graduate[k];
        Student S[] = new Student[k];
        for(int i=0;i<k;i++)
        {
            Ug[i] = new Undergraduate();
            G[i]= new Graduate();
            S[i]= new Student();
            S[i].set1(name=x.nextLine());
             S[i].set2(sex=x.nextLine());
            S[i].set3(sno=x.nextInt());
            S[i].set4(chinaGreade=x.nextInt());
             S[i].set5(mathGreade=x.nextInt());
             S[i].set6(EnglishGreade=x.nextInt());
            
               
        }
        for(int i=0;i<k;i++)
        {
            G[i].judge1(S[i].get4(),S[i].get5(),S[i].get6());
            Ug[i].judge(S[i].get4(),S[i].get5(),S[i].get6());
        }
    }
}
class Student
{
    private String name;
    private String sex;
    private int sno;
    private int chinaGreade;
    private int mathGreade;
    private int EnglishGreade;
    public void set1 (String name)
    {
        this.name = name;
    }
    public void set2(String sex)
    {
        this.sex = sex;
    }
    public void set3(int sno)
    {
        this.sno = sno;
    }
    public void set4(int chinaGreade)
    {
        this.chinaGreade = chinaGreade;
    }
    public void set5(int mathGreade)
    {
        this.mathGreade = mathGreade;
    }
    public void set6(int EnglishGreade)
    {
        this.EnglishGreade = EnglishGreade;
    }
    public String get1()
    {
        return name;
    }
    public String get2()
    {
        return sex;
    }
    public int get3()
    {
        return sno;
    }
    public int get4()
    {
        return chinaGreade;
    }
    public int get5()
    {
        return mathGreade;
    }
    public int get6()
    {
        return EnglishGreade;
    }
   
}

class Undergraduate extends Student
{   
    public void judge(int a,int b,int c)
    {
    if((a+b+c)/3>60)
        System.out.println("jege");

     }
}
class Graduate extends Student
{
    public void judge1(int a,int b,int c)
    {
    if((a+b+c)/3>60)
        System.out.println("Graduge_jege");

     }
}


出现的异常：
请输入人数

1
g
b
Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Unknown Source)
    at java.util.Scanner.next(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at StudentDemo.StudentDemo.main(StudentDemo.java:32)


求指点

谢谢，很有帮助

懂了，非常感谢。