import java.util.Scanner;

class B{
    int a[];
    B(int b){
        //int m;
        for(int i=0;i<b;i++){
            Scanner nn = new Scanner(System.in);
            a[i] = nn.nextInt();
        }
    }

/*int Partition(int first, int end)
{  
    int temp;
    int i=first;
    int j=end;
    while(i<j)
    {
        while(i<j && r[i] <= r[j])
            j--;
        if(i<j){
                 temp=r[i];
                 r[i]=r[j];
                 r[j]=temp;
                 i++;
        }
        while(i<j && r[i] <= r[j])
            i++;
        if(i<j){
                 temp=r[i];
                 r[i]=r[j];
                 r[j]=temp;
                 j++;
        }
    }

return i;
}

void QuickSort( int first, int end)
{
    int pivot;
    if(first < end){
    pivot = Partition(first, end);
    QuickSort( first, pivot-1);
    QuickSort( pivot+1, end);
    }
}
}*/
    void print(){
      for(int i=0;i<a.length;i++){
          System.out.print(a[i]+" ");
      }
    }
}

class A {

    /**
     * @param args
     */
    public static void main(String[] args) {
        int b;
        Scanner nn = new Scanner(System.in);
        b = nn.nextInt();
        System.out.print(b);
        B bb= new B(b);
        bb.print();
    }

}

数组没有初始化，a = new int[b];
以后问问题最好说的详细一点，把错误信息也贴出来，这样更方便别人给你解答