室内检查井:Java编程关于”英塔普特”高手帮忙啊总不成功

import java.io.*;
public class TowerDemo{
public static void main(String args[]) throws IOException
{BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
int x,i=1;
int j=1;
char a;
int n;
char[][] a;

String p1;
String p2;
a=newchar[10][10];
system.out.println("请输入打算建多少层塔");
p1=br.readLine();
x=Integer.parseInt(p1);

system.out.println("请问是向上建还是向下建（0-向上；1-向下)");
p2=br.readLine();
n=Integer.parseInt(p2);
switch(n){
case1:{

for (i=1;i<=x;i++){
for(j=1;j<i;j++){
if(j>x-i&&j<x+i){
a[i][j]="*";
}
else{
a[i][j]=" ";
}
}
}
break;
case0:
{
for(i=i;i<=x;i++){
for(j=1;j<i;j++){
if(j>i-1&&j<=2*x-i+1){
a[i][j]="*";
}
else{
a[i][j]=" ";
}
}
}
}
break;
default:System.out.println("只能选择0和1");
}

for(i=1;i<=x;i++){
for(j=1;j<=2x;j++){
system.out.print(a[i][j]);
}
system.out.print("\n");

}

}
}}