1,由A-Z、a-z、0-9组成3位的字符密码,设计一个算法,列出并打印所有可能的密码组合。
由于控制台容纳能力有限,故将其写到文本文件中。
没人会耐心等你把这61个字母输完(程序执行ms,输入程序一分钟,自己手动输入四五分钟),这时用程序把内容生成,然后复制,,,
/*为什么输入程序这么多比手动输入'A','B','C',…'a','b','c'...'1','2,'3'...'8','9'快 *因为需要输入不同的字母,数字,引号括住,还得逗号隔开。 *但是程序都是生成的,输入程序只要半分钟,最多一分钟,执行时间几乎能忽略 */ public class ZiFuChuanShengCheng{//这代码程序生成,为方便,可简化为public class A public static void main(String[] args){//自动生成 for(int a='A';a<='Z';a++){//for循环自动生成轮廓,填充即可 System.out.print("'"+(char)a+"',"); } /*下面两个循环由第一个按住Ctrl+ALT+↓下箭头得到*/ for(int a='a';a<='z';a++){ System.out.print("'"+(char)a+"',"); } for(int a='1';a<='9';a++){ System.out.print("'"+(char)a+"',"); } System.out.println(); } }
得到:'A','B','C','D','E','F','G','H','I','J','K','L','M',
'N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
'a','b','c','d','e','f','g','h','i','j','k','l','m',
'n','o','p','q','r','s','t','u','v','w','x','y',
'z','1','2','3','4','5','6','7','8','9',
java实现:
package com.starain.mimabianli; import java.io.BufferedWriter; import java.io.File; import java.io.FileWriter; import java.io.IOException; public class BianLiMiMa { public static void main(String[] args) { try { long time1 = System.currentTimeMillis(); int count = 1; char mima[] = {'A','B','C','D','E','F','G','H','I','J','K','L','M', 'N','O','P','Q','R','S','T','U','V','W','X','Y','Z', 'a','b','c','d','e','f','g','h','i','j','k','l','m', 'n','o','p','q','r','s','t','u','v','w','x','y','z', '1','2','3','4','5','6','7','8','9'}; File file1 = new File("D:/mima.txt"); BufferedWriter bfile1 = new BufferedWriter(new FileWriter(file1)); for(int i = 0;i <61;i++){ for(int j=0;j<61;j++){ for(int k = 0; k <61;k++){ count++; bfile1.write(mima[i]); bfile1.write(mima[j]); bfile1.write(mima[k]); bfile1.newLine(); } } } long time2 = System.currentTimeMillis(); System.out.println("用时:"+(time2-time1)+"ms"); bfile1.close(); } catch (IOException e) { System.out.println("error"); } } }
C实现
1 #include<stdio.h> 2 #include <time.h> 3 void main(){ 4 clock_t t1 , t2; 5 t1 = clock(); 6 FILE *file1 =fopen("D:/mima2.txt","w"); 7 char mima[] = {'A','B','C','D','E','F','G','H','I','J','K','L','M', 8 'N','O','P','Q','R','S','T','U','V','W','X','Y','Z', 9 'a','b','c','d','e','f','g','h','i','j','k','l','m', 10 'n','o','p','q','r','s','t','u','v','w','x','y','z', 11 '1','2','3','4','5','6','7','8','9'}; 12 for(int i = 0;i <61;i++){ 13 for(int j=0;j<61;j++){ 14 for(int k = 0; k <61;k++){ 15 fputc(mima[i],file1); 16 fputc(mima[j],file1); 17 fputc(mima[k],file1); 18 fputs(" ",file1); 19 } 20 } 21 } 22 t2 = clock(); 23 printf("用时%dms ",(t2-t1)); 24 }
用时真的能可以忽略了。。。
2、实现字符串反转函数
String s = "abcdefghijklm";
C++
#include <iostream> #include <string> using namespace std; void main(){ String s = "abcdefghijklm"; cout << s << endl; int len = s.length(); char temp = 'a'; for(int i = 0; i < len/2; i++){ temp = s[i]; s[i] = s[len - 1 - i]; s[len - 1 - i] = temp; } cout << s; }
java
package com.starain.mianshi; public class FanZhuan { public static void main(String[] args) { String str1 = "abcdefghijklm"; String str2 = ""; for(int i=str1.length()-1;i>=0;i--){ str2+=str1.charAt(i); } System.out.println(str2); } }