In a string, four algorithms for counting the number of uppercase letters, the number of lowercase letters, and the number of other characters

Title Description: Write the program, the output string of uppercase letters, lowercase small mother and the number of other. If there is a string "Helle, this is A test textfile.123456, Tannk you!!", the number of uppercase letters: 3, lowercase letters: 29, the number of other characters: 18.

Here are four algorithms, the first of which is a good understanding, but also a hard coding problem, and the other three ways to use the Java-language JDK provided by the API.

Method One:

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[Java]View PlainCopy
 
 

  
  

  
Method One: In the use of Unicode code for each character between A~z, call the JDK
  
  

  
The Charat of the string class is used to take out each character of the strings and compare them to determine
  
  

  

  
  

  
Class Findletter {
  
  

  
public static void Main (string[] args) {  
  
  

  
String str = "Helle, this is A test textfile.123456, Tannk you!!"; 
  
  

  
int upcount = 0; 
  
  

  
int lowcount = 0; 
  
  

  
int othercount = 0; 
  
  

  

  
  

  
For (int i = 0; i < str.length (); i++) {  
  
  

  
char c = str.charat (i); 
  
  

  
if (c >= ' a ' && c <= ' Z ') {  
  
  

  
lowcount++;
  
  

  
} Else if (c >= ' A ' && c <= ' Z ') {   
  
  

  
upcount++;
  
  

  
} Else {
  
  

  
othercount++;
  
  

  
}
  
  

  
}
  
  

  
System.out.println ("Number of uppercase females:" + upcount); 
  
  

  
System.out.println ("number of lowercase letters:" + lowcount); 
  
  

  
System.out.println ("number of other characters:" + othercount); 
  
  

  
}
  
  

  
}
 
 
Method Two:
[Java]View PlainCopy
 
 

  
  

  
Method Two: The Isuppercase method and Islowercase method of character class using JDK
  
  

  

  
  

  
Class FindLetter1 {
  
  

  
public static void Main (string[] args) {  
  
  

  
String str = "Helle, this is A test textfile.123456, Tannk you!!"; 
  
  

  
int upcount = 0; 
  
  

  
int lowcount = 0; 
  
  

  
int othercount = 0; 
  
  

  

  
  

  
For (int i = 0; i < str.length (); i++) {  
  
  

  
char c = str.charat (i); 
  
  

  
if (Character.isuppercase (c)) {
  
  

  
upcount++;
  
  

  
} Else if (Character.islowercase (c)) { 
  
  

  
lowcount++;
  
  

  
} Else {
  
  

  
othercount++;
  
  

  
}
  
  

  
}
  
  

  
System.out.println ("number of capital letters:" + upcount); 
  
  

  
System.out.println ("number of lowercase letters:" + lowcount); 
  
  

  
System.out.println ("number of other letters:" + othercount); 
  
  

  
}
  
  

  
}
 
 

Method Three:
[Java]View PlainCopy
 
 

  
  

  
Method Three: First define two strings A to Z and A to Z, and then remove each letter of the STR string,
  
  

  
Use the IndexOf () method to determine if the character is in this defined string, in the uppercase line,
  
  

  
The counter of the capital letter is added 1, in the lowercase letter this line, the lowercase letter adds one, otherwise the other letter calculator
  
  

  
Plus 1
  
  

  

  
  

  
Class FindLetter2 {
  
  

  
public static void Main (string[] args) {  
  
  

  
String low = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; 
  
  

  
String up = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; 
  
  

  
int lowcount = 0; 
  
  

  
int upcount = 0; 
  
  

  
int othercount = 0; 
  
  

  
String str = "Helle, this is A test textfile.123456, Tannk you!!"; 
  
  

  

  
  

  
For (int i = 0; i < str.length (); i++) {  
  
  

  
char c = str.charat (i); 
  
  

  
if (Low.indexof (c)! =-1) { 
  
  

  
lowcount++;
  
  

  
} Else if (Up.indexof (c)! =-1) {  
  
  

  
upcount++;
  
  

  
} Else {
  
  

  
othercount++;
  
  

  
}
  
  

  
}
  
  

  
System.out.println ("number of capital letters:" + upcount); 
  
  

  
System.out.println ("number of lowercase letters:" + lowcount); 
  
  

  
System.out.println ("number of other letters:" + othercount); 
  
  

  
}
  
  

  
}
 
 

Method Four:
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Convert str to uppercase and lowercase uppercase with su lowercase SL
  
  

  
Then count the numbers by comparing them to the original string.
  
  

  

  
  

  
Class FindLetter3 {
  
  

  
public static void Main (string[] args) {  
  
  

  
String str = "Helle, this is A test textfile.123456, Tannk you!!"; 
  
  

  
String SU = Str.touppercase ();
  
  

  
String SL = Str.tolowercase ();
  
  

  
int lowcount = 0; 
  
  

  
int upcount = 0; 
  
  

  
int othercount = 0; 
  
  

  
For (int i = 0; i < str.length (); i++) {  
  
  

  
char charstr = Str.charat (i); 
  
  

  
char Charsu = Su.charat (i); 
  
  

  
char charsl = Sl.charat (i); 
  
  

  

  
  

  
//If it is not a letter and is a different character, it is counted directly with Othercount
  
  

  
if (Character.isletter (CHARSTR)) {
  
  

  
//If the original string is equal to the converted uppercase string, the original character is uppercase,
  
  

  
//lowercase letters if they are equal to lowercase letters
  
  

  
if (charstr = = Charsu) {
  
  

  
upcount++;
  
  

  
} Else if (charstr = = charsl) { 
  
  

  
lowcount++;
  
  

  
}
  
  

  
} Else {
  
  

  
othercount++;
  
  

  
}
  
  

  
}
  
  

  

  
  

  
System.out.println ("number of capital letters:" + upcount); 
  
  

  
System.out.println ("number of lowercase letters:" + lowcount); 
  
  

  
System.out.println ("number of other letters:" + othercount); 
  
  

  
}
  
  

  
}
 
 

All four of these algorithms have the correct output:
Number of capital letters: 3
Number of lowercase letters: 29
Number of other letters: 18
In a string, four algorithms for counting the number of uppercase letters, the number of lowercase letters, and the number of other characters