字符串中各类字符的总和汇总 字符串中子串个数查询实现

各类字符总和

import java.util.Scanner;

public class StringTest
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);

System.out.println("请输入一行字符串：");
String s = sc.nextLine();

int big=0,small=0,space=0,other=0;
for(int i=0;i<s.length();i++)
{
char c = s.charAt(i);
if(c>='a' && c<='z')
small++;
if(c>='A' && c<='Z')
big++;
if(c == 32)
space++;
else
other++;
}
System.out.println("小写字母为：" + small + " 大写字母为："+ big + " 空格为：" + space + " 其他字符为" + other);
}
}

子串个数查询：

使用subString

import java.util.*;

public class StringTest2
{

public static void main(String args[])
{

Scanner sc = new Scanner(System.in);
System.out.println("请输入一行字符串：");
String s = sc.nextLine();
System.out.println("请输入要查询个数的字符串");
String aim= sc.nextLine();
int number = 0;
for(int i = 0;i<=s.length()-aim.length();i++)
{
if(s.substring(i,i+aim.length()).equals(aim))
{
number++;
i = i + aim.length() - 1;
}
}
System.out.println("字符串"+aim+"的个数为"+number+"!!!");
}
}

使用indexOf：

import java.util.*;
public class StringTest3
{
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.println("请输入一行字符串：");
String s = sc.nextLine();
System.out.println("请输入要查询个数的字符串");
String aim= sc.nextLine();
int number=0;
int start = 0;
while(s.indexOf(aim,start)>=0 && start < s.length())
{
number++;
start = s.indexOf(aim,start) + aim.length();
}
System.out.println("出现的次数为" + number + "!");

}
}