第一题
public class Ex4_1 {
String str;
public Ex4_1(String str) {
this.str = str;
}
int getlength() {
return str.length();
}
public static void main(String[] args) {
Ex4_1 test = new Ex4_1("Hello");
System.out.println("字符串是:" + test.str + " 长度为:" + test.getlength());
}
}
第二题
import java.util.*;
import java.io.*;
public class Ex4_2 {
public static void main(String[] args) {
String str1 = new String();
String str2 = new String();
char ch;
Scanner reader = new Scanner(System.in);
System.out.println("输入字符串:");
str1 = reader.nextLine(); //输入字符串
System.out.println("输入要删除的字符:");
str2 = reader.nextLine(); //输入穿要删除的字符 ,以字符串的形式输入
ch = str2.charAt(0); //将字符串str2转换为字符
str1 = str1.replace(ch, ' '); //用空格替代指定字符
System.out.println("删除字符后的字符串 " + str1);
}
}
第三题
class Ex4_3 {
public static void main(String[] args) {
String s = "cat223dog456nice25ttt98";
boolean old_tag = false; // 表示开始不是数字
boolean tag = false;
int n = 0; // 数字组计数
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
tag = c >= '0' && c <= '9'; // 是否为数字
if (!old_tag && tag) n++;
old_tag = tag;
}
System.out.print("共有数字段 " + n + " 个");
}
}