Java小程序(二)

 1 public class Demo {
 2     public static void main(String args[]){
 3         
 4         int arr[]=new int [20];
 5         arr[0]=1;
 6         arr[1]=1;
 7         System.out.print(arr[0]+"  ");
 8         System.out.print(arr[1]+"  ");
 9         for(int i=2;i<20;i++){
10             arr[i]=arr[i-1]+arr[i-2];
11             System.out.print(arr[i]+"  ");
12         }
13     }
14 
15 }

 1 public class Demo {
 2     public static void main(String args[]){
 3 
 4         int num1=1;
 5         int num2=1;
 6         System.out.print("  "+num1);
 7         System.out.print("  "+num2);
 8         for(int i=3;i<=20;i++){
 9             int num3=num1+num2;
10             num1=num2;
11             num2=num3;
12             System.out.print("  "+num3);
13         }
14     }
15 
16 }

 1 public class Demo {
 2     public static void main(String[] args) {
 3         
 4         for(int i=1;i<=20;i++){
 5             System.out.print("  "+f(i));
 6         }
 7     }
 8     public static int f(int n) {
 9         if (n==1||n==2) 
10             return 1;
11         else
12             return f(n-1)+f(n-2);
13     }
14 
15 }

 1 public class MatrixDemo {
 2     public static void main(String args[]){
 3         
 4         int i,j;
 5         int arr1[][]={{1,2,3},{4,5,6},{7,8,9},{10,11,12}};
 6         int arr2[][]=new int [3][4];
 7         
 8         System.out.println("矩阵转置前：");
 9         for(i=0;i<4;i++){
10             for(j=0;j<3;j++){
11                 System.out.print(arr1[i][j]+"   ");
12             }
13             System.out.println();
14         }
15         
16         System.out.println("矩阵转置后：");
17         for(i=0;i<4;i++){
18             for(j=0;j<3;j++){
19                 arr2[j][i]=arr1[i][j];
20             }
21         }
22         for(i=0;i<3;i++){
23             for(j=0;j<4;j++){
24                 System.out.print(arr2[i][j]+"  ");
25             }
26             System.out.println();
27         }
28     }
29     
30 }

 1 public class MaxminDemo {
 2     public static void main(String args[]){
 3         
 4         int arr[][]={{36,45,90,3},{24,39,10,4},{36,72,66,5},{64,88,120,6}};
 5         int i,j,m=0,n=0,a=0,b=0;
 6         int max=arr[0][0],min=arr[3][3];
 7         
 8         System.out.println("4阶矩阵：");
 9         for(i=0;i<4;i++){
10             for(j=0;j<4;j++){
11                 System.out.print(arr[i][j]+"  ");
12                 
13                 if(max<arr[i][j]){
14                     max=arr[i][j];
15                     a=i;
16                     b=j;
17                 }
18                 if(min>arr[i][j]){
19                     min=arr[i][j];
20                     m=i;
21                     n=j;
22                 }
23             }
24             System.out.println();
25         }
26         System.out.println("矩阵中最大的数Max="+max);
27         System.out.println("该数位于矩阵的第"+a+"行"+"第"+b+"列");
28         System.out.println("矩阵中最小的数Min="+min);
29         System.out.println("该数位于矩阵的第"+m+"行"+"第"+n+"列");
30     }
31 
32 }