编译出现需要class或interface或enum怎么解决？

Question

import java.util.Scanner;
class Work {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("请输入你要生成的随机数的个数：");
int n = sc.nextInt();
for (int j = 0; j < n; j++) {
double i = Math.random() * 100000000;
System.out.println((int) i);
}
}
}
int i,j,t;
for(i=1; i<N; i++) { //插入法排序数组
t=a[i];
for(j =i-1; j>=0;j--){
if(t > a[j]){
break;
}
else{
a[j+1] = a[j];
}
}
a[j+1] = t;
}
System.out.println(Arrays. toString(a));
Scanner scanner = new Scanner(System.in);
System.out.println("输入一个字符，程序判断该字符是否在数组中:");
char c= scanner.next().charAt(0);

  int number = (int)c;
  int count =0 ;
  end = N;
  middle=(start+end)/2;
  while(number!=a[middle]){
       if(number>a[middle])
          start=middle;
       else if(number<a[middle])
          end=middle;
       middle=(start+end)/2;
       count++;
      if(count>N/2)
         break;
  }
  if(count>N/2)
     System.out.printf("%d不在数组中.\n",number);
  else
     System.out.printf("%d在数组中.\n",number);

}
}

Answer 1

绿色的框代表一个整体（一个完整的类），下面的内容你都没有将其放到类的方法里面，另外N又是从哪里来的？java是一门强类型语言，区分大小写的，N和n没有半点关系