java 经典范例

package 开阳;
import java.util.Scanner;
public class image {
public static void main(String[] args){
Scanner scan = new Scanner(System.in);
System.out.println("请输入一个奇数，用来构造一个空心菱形");
int key =scan.nextInt();
System.out.println();
if (key%2==0){
System.out.println("您输入的是一个偶数");
}
else{
printHollowRhombus(key);
}
}
public static void printHollowRhombus(int size){
for(int i=1;i<(size+1)/2;i++){
for(int j=1;j<=size;j++)
if (Math.abs((size+1)/2-j)==i-1){
System.out.print("*");
}
else{
System.out.print(" ");
}
System.out.println();
}
for(int i=(size+1)/2;i>0;i--){
for(int j=1;j<=size;j++){
if (Math.abs((size+1)/2-j)==i-1){
System.out.print("*");
}
else{
System.out.print(" ");
}

}
System.out.println();
}
}
}