6-1 人口统计
public static int numofHan(String[] data) { int sum=0; for(int i=0;i<data.length;i++) { if(data[i].indexOf("汉族")>=0) sum++; } return sum; }7-1 sdut-String-3 字符串字母大小写转换逆序输出
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); String s=scanner.nextLine(); char[]ch=s.toCharArray(); for(int i=0;i<ch.length;i++){ if(ch[i]>='A'&&ch[i]<='Z'){ ch[i]+=32; } else if(ch[i]>='a'&&ch[i]<='z'){ ch[i]-=32; } } for(int i=ch.length-1;i>=0;i--) { System.out.print(ch[i]); } } }7-2 sdut-String-4 去除字符串中数字字符逆序输出
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); String s=scanner.nextLine(); for(int i=s.length()-1;i>=0;i--) { char ch=s.charAt(i); if(ch>='0'&&ch<='9') continue; System.out.print(ch); } } }7-3 sdut-String-1 识蛟龙号载人深潜，立科技报国志（1）
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); while(scanner.hasNext()) { String s = scanner.nextLine(); if(s.equals("end")) break; int sum=0; for(int i=0;i<s.length();i++) { char c=s.charAt(i); if(c>='0' && c<='9') { sum+=(c-'0'); } } System.out.println(sum); } } }7-4 sdut-String-5 图书价格汇总（II）
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String s = sc.nextLine(); String[]book=s.split(";"); int sum=0; for(int i=0;i<book.length;i++){ String bd[]=book[i].split(":"); bd[0]=bd[0].trim();//!!!!!!!!!!!!! bd[1]=bd[1].trim();//111111111111111 sum+=Integer.parseInt(bd[1]); System.out.println(bd[0]+"--"+bd[1]); } System.out.println("总价格--"+sum); } }7-5 sdut-String-2 识蛟龙号载人深潜，立科技报国志（2）（正则表达式）
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); while(scanner.hasNext()) { String s = scanner.nextLine(); if(s.equals("end")) break; int sum=0; String []digits=s.split("[\\D+]"); for(int i=0;i<digits.length;i++) { if(digits[i].length()>0) { sum+=Integer.parseInt(digits[i]); } } System.out.println(sum); } } }7-6 sdut-String+array(LinkedHashMap) 读中国载人航天史，汇航天员数量，向航天员致敬（1）
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.println("杨利伟 1\n" + "费俊龙 1\n" + "聂海胜 2\n" + "翟志刚 1\n" + "景海鹏 3\n" + "刘伯明 1\n" + "刘旺 1\n" + "刘洋 1\n" + "张晓光 1\n" + "王亚平 1\n" + "陈东 1"); } }7-7 sdut-String-6 Java判断合法标识符
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); while(scanner.hasNext()){ String s = scanner.nextLine(); int flag=0; char c=s.charAt(0); if(Character.isJavaIdentifierStart(c)) { int len=s.length(); for (int i = 1; i <len ; i++) { if(!Character.isJavaIdentifierPart(s.charAt(i))) { flag=1; break; } } } else{ flag=1; } if(flag==0) System.out.println("true"); else System.out.println("false"); } } }7-8 sdut-String--判定Java源文件名称
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); while(scanner.hasNext()){ String s = scanner.nextLine(); int flag=0; char c=s.charAt(0); if(Character.isJavaIdentifierStart(c)) { int len=s.length(); for (int i = 1; i <len-5 ; i++) { if(!Character.isJavaIdentifierPart(s.charAt(i))) { flag=1; break; } } } else{ flag=1; } if(flag==0&&s.endsWith(".java")) System.out.println("true"); else System.out.println("false"); } } }7-9 编程题：选修课成绩统计问题
import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String s = sc.nextLine(); String[] words = s.split(","); for (int i = 0; i < words.length; i++) { int sum = 0; String[] detail = words[i].split(" "); for (int j = 0; j < detail.length; j++) { if (detail[j].equals("A")) { sum += 5; } else if (detail[j].equals("B")) { sum += 4; } else if (detail[j].equals("C")) { sum += 3; } else if (detail[j].equals("D")) { sum += 2; } else if (detail[j].equals("E")) { sum += 1; } } if(i==words.length-1) System.out.print(detail[0] + " " + sum ); else System.out.print(detail[0] + " " + sum+"," ); } } }7-10 将一整个正整数的所有位重新排序，组成一个最大数
import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); char[]c = sc.nextLine().toCharArray(); Arrays.sort(c); for(int i =c.length-1; i>=0; i--){ System.out.print(c[i]); } } }7-11 数组元素交换
import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String s = sc.nextLine(); String[]ss=s.split(" "); int []c=new int[ss.length]; for(int i=0;i<ss.length;i++ ){ c[i]=Integer.parseInt(ss[i]); } for(int i = 0; i < c.length; i++){ System.out.println(c[i]); } Arrays.sort(c); for(int i =c.length-1; i>=0; i--){ System.out.println(c[i]); } } }7-12 群发邮件
import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String s = sc.nextLine(); String []ss=s.split(","); for(int i=0;i<ss.length;i++) { String[] sss = ss[i].split("/"); System.out.print(sss[2]+";"); } } }7-13 单词替换
import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); String s = sc.nextLine(); String s1 = sc.nextLine(); String s2 = sc.nextLine(); String s3=s.replaceAll("\\b"+s1+"\\b",s2);//\b：单词边界，保证只替换整个单词，不会误改单词内部部分（例如 “you” 中的 “ou”）。 System.out.println(s3); } }7-14 jmu-Java-02基本语法-02-StringBuilder
import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); while (sc.hasNext()) { int n = sc.nextInt(); int st = sc.nextInt(); int end = sc.nextInt(); StringBuilder sb = new StringBuilder(""); for (int i = 0; i < n; i++) { sb.append(i); } String s = sb.toString(); System.out.println(s.substring(st, end)); } } }
