public class Test {
public static void main(String[] args) {
analyzeAddition(5, true);
analyzeAddition(5, false);
}
/**
* <p>
* 打印菱形
* </p>
*
* @param boundary
* 菱形增大的最大行数
* @param addtional
* 在达到最大行数之后,开始缩小,而字母是否继续增大,true为继续增大,false为从最大字母开始减小
*/
static void analyzeAddition(int boundary, boolean addtional) {
char start = 'A';
for (int i = 1; i <= boundary; i++) {
// 输出需要填充的空格数
for (int j = 0; j < boundary - i; j++) {
System.out.print(' ');
}
for (int j = 0; j < i; j++) {
System.out.print(start++ + " ");
}
System.out.println();
}
start--;
for (int i = boundary - 1; i > 0; i--) {
for (int j = 0; j < boundary - i; j++) {
System.out.print(' ');
}
for (int j = i; j >= 1; j--) {
System.out.print(addtional ? ++start + " " : --start + " ");
}
System.out.println();
}
}
}
package collections;
import java.util.ArrayList;
import java.util.List;
public class ssdss
{
public static void main(String[] args)
{
List<String> list = new ArrayList<String>();
list.add(" A");
list.add(" B C");
list.add(" D E F");
list.add("G H I J");
for (int i = 0; i < 4; i++) {
System.out.println(list.get(i));
}
for (int i = 2; i >= 0; i--) {
System.out.println(list.get(i));
}
追问很抱歉,刚才忘了写要用循环语句