class student1{
    private String name;
    private String sexy;
    private String duty;
    private double score;
    private int id;
   
   
    public void set(String name , String sexy ,int id ,double score ,String duty){
        this.name = name;
        this.sexy = sexy;
        this.id =id;
        this.score = score;
        this.duty = duty;
        }
    public String getName(){
        return name;
        }
    public String getSexy(){
        return sexy;
        }   
    public int getId(){
        return id;
        }   
    public double getScore(){
        return score;
        }   
    public String getDuty(){
        return duty;
        }
       
   
    public void info(){
        System.out.println("学生姓名："+name+"性别:"+sexy+"职务"+duty+ id);
        }   
  public void print(){
      System.out.println(score);
      }
    }
   
    public class student{
        public static void main(String arges[]){
            student st1 = new student();
            student st2 = new student();
            student st3 = new student();
         
         
         
         
         
          st1.info("张三","男","班长","1");
          st2.info("李四","男","学生","2");
            st3.info("娜娜","女","学生","3");
           
            st1.print("90.0");
            st2.print("85.2");
            st3.print("10");
           
           
            }
       
        }
        红色的地方说找不到标识符

class student1{  你用的类名是 student1
            student st1 = new student();
            student st2 = new student();
            student st3 = new student();
这3行都要改 student1 st1 = new student1();  再试试看

   这样的代码 再仔细看看吧 ！  错误不难找的，楼上说的应该是对的 ，把那里改了吧

写代码习惯要好
1、类名首字母大写
2、一个java文件一个类（个人习惯，除非有必要否则不要写私有的类）
3、类名要有意义
4、使用package

看完楼主的代码，定义了一个student1的类，但为什么再定义一个student类呢？
student类中除了main函数什么都没有，那么完全可以将main函数写到student1类中

顶楼上的        !!!

领教了   今后多多注意