1 public class ForTest {
2 public static void main(String args[]){
3 //直角三角形
4 /*for(int i = 1; i <= 5; i++){
5 for(int j = 1;j <= i;j++){
6 System.out.print("*");
7 }
8 System.out.print("\n");
9 }*/
10 //等腰三角形
11 /*for(int i = 1; i <=5;i++ ){
12 for(int j = 1; j <= 5-i;j++){
13 System.out.print(" ");
14 }
15 for(int k = 1; k <= 2 * i - 1; k++){
16 System.out.print("*");
17 }
18 System.out.print("\n");
19 }*/
20 //菱形
21 /*for(int i = 1; i <= 5;i++){
22 for(int j = 1; j <= 5-i; j++){
23 System.out.print(" ");
24 }
25 for(int k = 1; k <= 2*i-1; k++){
26 System.out.print("*");
27 }
28 System.out.print("\n");
29 }
30 for(int l = 1; l <= 4; l++){
31 for(int m = 1; m <= l; m++){
32 System.out.print(" ");
33 }
34 for(int n = 1; n <= 9 - 2 * l; n++){
35 System.out.print("*");
36 }
37 System.out.print("\n");
38 }*/
39
40
41 //求 1！+2！+3！+....+9!+10!
42 /*int sum = 0;
43 for(int i = 1; i <= 10; i++){
44 int n = 1;
45 for(int j = 1;j <= i;j++){
46 n *= j;
47 }
48 sum += n;
49 }
50 System.out.print(sum);*/
51 //判断素数
52 /*System.out.println("请任意输入一个大于1的整数：");
53 Scanner sc = new Scanner(System.in);
54 int n = sc.nextInt();
55 boolean c = false;
56 for(int i = 2;i <= n-1;i++){
57 if(n % i==0){
58 c = true;
59 }
60 }
61 if(c){
62 System.out.println("该数不是素数");
63 }else{
64 System.out.println("该数是素数");
65 }*/
66 //打印9*9乘法口诀表
67 for(int i = 1;i<=9;i++){
68 int n = 1;
69 int j;
70 for(j = 1; j<=i;j++){
71 n = i * j;
72 System.out.print(j+"*"+i+"="+ n+"\t");
73 }
74 System.out.print("\n");
75 }
76 //打印100-200之内的所有素数
77 for(int i = 100; i<=200;i++){
78 int j;
79 for(j = 2; j<=i;j++){
80 if(i%j==0){
81 if(i == j){
82 System.out.println(i);
83 }
84 break;
85 }
86 }
87 }
