Java实验三

String01

 1 package com.itcast.atd.demo04;
 2 
 3 public class String01 {
 4     public static void main(String[] args) {
 5         String str="This is a text of java";
 6         int count = 0;
 7 
 8         for (int i = 0; i <str.length() ; i++) {
 9             if(str.charAt(i)=='s')
10                 count++;
11         }
12 
13         System.out.println(count);
14     }
15 }

String02

 1 package com.itcast.atd.demo04;
 2 
 3 public class String02 {
 4     public static void main(String[] args) {
 5         String str="This is a text of java";
 6         int count=0;
 7         int index=0;
 8         String ctr="is";
 9 
10         while((index=str.indexOf(ctr,index))!=-1){
11             index+=ctr.length();
12             count++;
13         }
14 
15         System.out.println(count);
16 
17     }
18 }

String03

package com.itcast.atd.demo04;

public class String04 {
    public static void main(String[] args) {
        String s="ddejidsEFALDFfnef2357 3ea";
        int lcount = 0,ucount = 0,icount = 0;

        for(int i=0;i<s.length();i++) {
            char c=s.charAt(i);//返回字符串第i个字符
            if(c>='a'&&c<='z')
                lcount++;
            else if(c>='A'&&c<='Z')
                ucount++;
            else
                icount++;
            }

        System.out.println(lcount);
        System.out.println(ucount);
        System.out.println(icount);
    }
}

运行结果：