学习Java28天（练习）

public class StringDemo5 { public static void main(String[] args) { //拼接数组 int[] arr = {1,2,3}; String str = arrToString(arr); System.out.println(str); } public static String arrToString(int[] arr){ if (arr==null){ return ""; } if (arr.length==0){ return "[]"; } String result ="[";; for (int i = 0; i < arr.length; i++) { if (i== arr.length-1){ result = result+arr[i]; }else { result = result+arr[i]+","; } } result = result + "]"; return result; } }

public class StringDemo6 { public static void main(String[] args) { //字符串反转 String result = reveser("abc"); System.out.println(result); } public static String reveser(String str){ String result = ""; for (int i = str.length()-1; i >=0; i--) { char c = str.charAt(i); result = result + c; } return result; } }

import java.util.Scanner; public class StringDemo7 { public static void main(String[] args) { //1.键盘录入一个金额 Scanner Sc = new Scanner(System.in); int money ; while (true){ System.out.println("请输入一个金额："); money = Sc.nextInt(); if (money >= 0 && money <= 9999999){ System.out.println(money); break; }else { System.out.println("金额无效"); } } String moneyStr = ""; while (true){ int ge = money%10; String CapitalNumber = getCapitalNumber(ge); moneyStr = CapitalNumber + moneyStr; money = money/10; if (money==0){ break; } } int count = 7-moneyStr.length(); for (int i = 0; i < count;i++){ moneyStr = "零" + moneyStr; } String[] arr = {"佰","拾","万","仟","佰","拾","元"}; String result = ""; for (int i = 0; i < moneyStr.length(); i++) { char c = moneyStr.charAt(i); result =result+ c+arr[i]; } System.out.println(result); } public static String getCapitalNumber(int number){ String[] str = {"零","壹","贰","叁","肆","伍","陆","柒","捌","玖"}; return str[number]; } }

public class StringDemo8 { public static void main(String[] args) { //1.获取一个手机号 String phoneNumber = "13112349468"; //2.截取手机号码前三位 String start = phoneNumber.substring(0,3); //3.截取手机号码后四位 String end = phoneNumber.substring(7); //4.拼接 String result = start+"****"+end; //5.打印 System.out.println(result); } }

public class StringDemo9 { public static void main(String[] args) { //1.定义一个身份证号码 String id = "123456789012345678"; //2.获取出生年月日 String year= id.substring(6,10); String month = id.substring(10,12); String day = id.substring(12,14); System.out.println("人物信息为："); System.out.println("出生年月日："+year+"年"+month+"月"+day+"日"); //3.获取性别 //利用ASCII码表 char gender = id.charAt(16); int num = gender - 48; if (num%2==0) { System.out.println("性别为：女"); }else { System.out.println("性别为：男"); } } }

public class StringDemo10 { public static void main(String[] args) { //1.获取说的话 String talk = "你玩的真好，以后不要再完了，SB,CNM"; //2.定义一个敏感词库 String[] arr = {"TMD","CNM","SB","MLGB"}; //3.把TMD替换为*** for (int i = 0; i < arr.length; i++) { talk = talk.replace(arr[i],"***"); } //4.打印结果 System.out.println(talk); } }