Java 練習：求指定字符串中大寫字母，小寫字母，其他字符分別的個數。

/*
public class Test1{
    public static void main(String[]args){
        String s = "abcdeEFHDKEI38475    ";
        char a[] = s.toCharArray();
        int lower = 0,upper = 0,other = 0;
        for(int i=0; i<a.length; i++){
            if(a[i]<='z' && a[i]>='a')    
                lower++;
            else if(a[i]<='Z' && a[i]>='A') 
                upper++;
            else 
                other++;
        }
             System.out.println(lower);
             System.out.println(upper);
             System.out.println(other);
    }
}
*/

/*
public class Test1{
    public static void main(String[]args){
        String s = "abcdeEFHDKEI38475    ";
        int lower = 0,upper = 0,other = 0;
        for(int i=0; i<s.length; i++){
            char c = s.charAt(i);
            if(c<='z' && c>='a')    
                lower++;
            else if(c <='Z' && c >='A') 
                upper++;
            else 
                other++;
        }
             System.out.println(lower);
             System.out.println(upper);
             System.out.println(other);
    }
}
*/
/*
public class Test1{
    public static void main(String[]args){
        String sL = "abcdefghijklmnopqrstuvwxyz";
        String sU = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String s = "abcdeEFHDKEI38475    ";
        int lower = 0,upper = 0,other = 0;
        for(int i=0; i< s.length(); i++){
            char c = s.charAt(i);
            if(sL.indexOf(c) != -1)    
                lower++;
            else if(sU.indexOf(c) != -1) 
                upper++;
            else 
                other++;
        }
             System.out.println(lower);
             System.out.println(upper);
             System.out.println(other);
    }
}
*/

public class Test1{
    public static void main(String[]args){
        String sL = "abcdefghijklmnopqrstuvwxyz";
        String sU = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String s = "abcdeEFHDKEI38475    ";
        int lower = 0,upper = 0,other = 0;
        for(int i=0; i< s.length(); i++){
            char c = s.charAt(i);
            if(Character.isLowerCase(c))    
                lower++;
            else if(Character.isUpperCase(c)) 
                upper++;
            else 
                other++;
        }
             System.out.println(lower);
             System.out.println(upper);
             System.out.println(other);
    }
}

　　關鍵思路：將字符串中每個字符提取出來，然后比較。具體查看Java API文檔。https://docs.oracle.com/javase/8/docs/api/index.html