[Java] Character judgment / character string formatting (AOJ11 --character count)

Determine if the alphabet is lowercase

• In the ASCII code table, ‘a’ to ‘z’ are consecutive
• The value of'b'is one greater than the value of'a'
• To write code that is true if c is lowercase
  c> ='a' && c <='z'

//A code that is true if c is a lowercase letter
public class Main {
    public static void main(String[] args){
    char c = 'c';
    
    System.out.printf("The character c you want to check is?  '%s'\n", c);
    /*True if c is a lowercase letter*/
    if (c >= 'a' && c <= 'z')
        System.out.println("c is lowercase");
    /*True if c is lowercase*/
    if (c >= 'a' && c <= 'z')        
        System.out.println("c is lowercase");
    else
        System.out.println("c is not lowercase");
    /*True if c is a number*/
    if (c >= '0' && c <= '9')       
        System.out.println("c is a number");
    else
        System.out.println("c is not a number");
    /*c is'+'Or'-'Then true*/
    if (c == '+' || c == '-')     
        System.out.println("c is the sign");
    else
        System.out.println("c is not a sign");
    }
}

The character c you want to check is?  'c'
c is lowercase
c is lowercase
c is not a number
c is not a sign

Repeated judgment with hasNext function of Scanner class

• Read input and still repeat to determine continuation
• Get the values in order from the front, true if you can still get the value, false if you can't get any more values

Scanner scanner = new Scanner(System.in);
while (scanner.hasNext()) {
    String str = scanner.next();
    System.out.println(str);
}

String formatting

• ** format method **: Convert value to any format using format specifier
• ** printf method **: Print as is instead of format. No newline character is added
• Format specifier: Notation for embedding values in format strings
• Output as it is except for the format specifier
• Example format specifier
• System.out.println (String.format ("% s weighs% d apples. "," Arukuma ", 70));
• 1 \ $, 2 \ $: Represents the 1st and 2nd arguments *% .2s: Specify the minimum width of the character string *% 8s: Specify the width of the character string. The left is blank for the shortage. Negative number, right blank *% # x: Hexadecimal display with 0 / 0x prefix *% .2e: 2 digits after the decimal point, exponential notation with e *% tF: Same as date% tY-% tm-% td *% td: time

import java.util.*;
import java.time.LocalDateTime;
import java.util.Locale;

public class Main {
 public static void main(String[] args) {
    System.out.println(String.format("%s weight is an apple%It is for d pieces.","Arukuma",70)); 
    System.out.println(String.format("%1$s weight is an apple%3$It is for d pieces.%1$s is fine.","Arukuma","Kitty",70)); //Arukumaの体重はりんご70個分です。Arukumaは元気です。
    //Specify the minimum width of the character string
    System.out.println(String.format("%.It's 2s.", "Arukuma"));       //This is Al.
    //Specify the width of the character string
    System.out.println(String.format("%It's 8s.", "Arukuma"));        //    Arukumaです。
    //Specify maximum number of digits
    System.out.println(String.format("Decimal number%08d", 12345));          //Decimal number00012345
    //Hexadecimal
    System.out.println(String.format("Hexadecimal%#x", 10));              //Hexadecimal0xa
    //Specify the number of digits after the decimal point
    System.out.println(String.format("Decimal point%.2f", 123.456));      //Decimal point123.46
    //index
    System.out.println(String.format("Exponent / lowercase%.2e", 123.456));  //Exponent / lowercase1.23e+02
    //Date and time
    var d = LocalDateTime.now();
    System.out.println(String.format("%tr", d));                      //03:42:23 AM
    System.out.println(String.format("%1$tY year%1$tm month%1$td day", d));  //October 31, 2020
    //Display with printf method
    System.out.printf("%.It's 2s.\n", "Arukuma");  
  }
}

Character count (ITP1-8)

Create a program that counts the number of each alphabet contained in the given English sentence. Note that lowercase and uppercase letters are not distinguished. Input You will be given one English sentence that spans multiple lines. Output Please output the number of each alphabet contained in the given English sentence in the format shown below: a: Number of a b: Number of b c: Number of c . . z: Number of z Constraints

• Number of characters contained in English <1200

import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        int alf[]=new int[26];
        while(scan.hasNext()){
            String str=scan.next().toLowerCase();
            for(int i=0;i<str.length();i++){
                char c=str.charAt(i);
                if('a'<=c&&c<='z'){
                    alf[str.charAt(i)-'a']++;
                }
            }
        }
        for(int i=0;i<26;i++)System.out.println((char)('a'+i)+" : "+alf[i]);
        scan.close();
    }
}