java 平时实验 乘法表 回文 闰年判断 字符统计

import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; public class tongji { public static void main(String[] args) { String s=null; int num[]; int ch[]; num= new int[26]; ch=new int[26]; for(int i=0;i<26;i++){num[i]=0;ch[i]=i;} try{ System.out.println("请输入一段英文："); BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); s=br.readLine(); }catch(IOException e){} panduan(s,num); sort(num,ch); int sum=0; for(int i=0;i<26;i++)sum=sum+num[i]; for(int i=0;i<26;i++) if(num[i]!=0) System.out.println((char)(ch[i]+'a')+"出现的比率为："+((float)num[i]/sum)); } public static void panduan(String s,int num[]) { int index = 0; for(int i=0;i<s.length();i++) { if(s.charAt(i)>='a'&&s.charAt(i)<='z') index=s.charAt(i)-'a'; else if(s.charAt(i)>='A'&&s.charAt(i)<='Z') index=s.charAt(i)-'A'; if(index!=-1) num[index]++; index=-1; } } public static void sort(int count[],int ch[]) { for(int m = 0 ; m < count.length ; m ++) { for(int n = m +1 ; n < count.length ; n++) { if(count[m] < count[n]) { int temp = count[m]; int t=ch[m]; count[m] = count[n];ch[m]=ch[n]; count[n] = temp;ch[n]=t; } } } } }