Loading... 闲着无聊看书时发现在String的介绍里写了判断以某字符串开头的方法。突然想到前几天做过的题目有优化的空间。将变量"zhengfu"删除,并使用String方法startsWith("-")判断首字母正负号 ## 下方为优化后代码 ```java package oj1002; import java.util.Scanner; /** * 该程序需注意分两种情况 * 1、有小数,将小数点作为索引,并保留两位小数或补全两位小数 * 2、无小数,直接按程序输出 * @author Renxing * @time 2020年11月24日 21:45 */ public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String in = sc.nextLine(); if(in.indexOf('.')==-1) { //char zhengfu=in.charAt(0); //if (zhengfu == '-') { if (in.startsWith("-")) { System.out.println(in.substring(1)+".00"); }else { System.out.println(in+".00"); } }else { String zhengshu = in.substring(0,in.indexOf('.')); //char zhengfu=in.charAt(0); String xiaoshu = in.substring(in.indexOf('.')); if (xiaoshu.length() >= 3) { xiaoshu = xiaoshu.substring(0,3); }else { xiaoshu = xiaoshu+'0'; } //if (zhengfu == '-') { if (in.startsWith("-")) { System.out.println(zhengshu.substring(1)+xiaoshu); }else { System.out.println(zhengshu+xiaoshu); } } } } ``` > ### 原文:<div class="preview"> <div class="post-inser post box-shadow-wrap-normal"> <a href="https://renxing.cc/java/38.html" target="_blank" class="post_inser_a no-external-link no-underline-link"> <div class="inner-image bg" style="background-image: url(https://renxing.cc/usr/themes/handsome/assets/img/sj/7.jpg);background-size: cover;"></div> <div class="inner-content" > <p class="inser-title">求无限制范围的实数绝对值</p> <div class="inster-summary text-muted"> 问题要点:输入的实数没有限制大小。考虑到float、double有限制范围、会出现精度丢失的问题,需要将输入的值接... </div> </div> </a> <!-- .inner-content #####--> </div> <!-- .post-inser ####--> </div> Last modification:August 26, 2021 © Allow specification reprint Support Appreciate the author AliPayWeChat Like 0 如果觉得我的文章对你有用,请随意赞赏