Java calculates the number of uppercase/lowercase letters and non-English letters in a string.

 

//One idea:

//Extract each character from the string, compare each character cyclically, and record the corresponding number of characters with three variables.

 

 

 

// The second silly way of thinking: first define 26 upper and lower case letters, and then search by index

 

// Method 3: Use the islowercase () and isuppercase () Methods of the character packaging class:

 

 Summary:

1. Java is very powerful, and it encapsulates some common methods. On the basis of understanding, it is of course easy-to-use.

2. It is very important to frequently check Java API documentation, a giant of Java.

3. The first two ideas contain clever ideas, which are of great help to extend thinking. If you do not know Java, you can solve it with the knowledge you have learned.

Common Mistakes

1.Note:A [I]<='Z'WrittenA [I]<="Z"The following error occurs: Operator<=Cannot be usedChar, java. Lang. String

Because double quotation marks indicate strings (StringType). Single quotes indicate characters (CharType ).

2. If the length () method I <J. Length () is written as I <jlength, an error is returned.