各种数字形状打印（嵌套for循环的应用）

1、12345

12345

12345

12345

<span style="font-size:14px;">public class Demo01 {

	public static void main(String[] args) {
		for(int i = 1;i <= 5; i++){
			for (int j = 1; j < 6; j++) {
				System.out.print(j);
			}
			System.out.println();
		}
	}

}

</span>

2、

11111

22222

33333

44444

55555

<span style="font-size:14px;">public class Demo02 {

	public static void main(String[] args) {
		for (int i = 1; i <= 5; i++) {
			for (int j = 1; j <= 5; j++) {
				System.out.print(i);
			}
			System.out.println();
		}
	}

}</span>

3、

1

22

333

4444

55555

<span style="font-size:14px;">public class Demo03 {

public static void main(String[] args) {
for (int i = 1; i <= 5; i++) {
for (int j = 1; j <= i; j++) {
System.out.print(i);
}
System.out.println();
}
}

}</span>

4、

1

12

123

1234

12345

<span style="font-size:14px;">public class Demo04 {

	public static void main(String[] args) {
		for (int i = 1; i <= 5; i++) {
			for (int j = 1; j <= i; j++) {
				System.out.print(j + " ");
			}
			System.out.println();
		}
	}

}</span>

5、  5

454

34543

2345432

123454321

<span style="font-size:14px;">public class Homework {

	public static void main(String[] args) {

		  for(int i=5;i>0;i--){
			  for(int j=i-1;j>0;j--){
				  System.out.print(" ");
				  }
			  for(int j=i;j<5;j++){
				  System.out.print(j);
				  }
			  for(int j=5;j>=i;j--){
				  System.out.print(j);
				  }
			  System.out.println();
			  } 

			System.out.println("=========================="); 

			for(int i = 5;i >= 0;i--){
				String txt = "";
				for(int k = 1;k < (6 -i);k++){
					txt = (6 - k) + txt;
				}
				for(int o = txt.length();o < 5;o++){
					txt = " " + txt;
				}
				txt += new StringBuffer(txt).reverse().toString().substring(1);
				System.out.println(txt);
			}

		  }
}
</span>