Java 選單驅動程式，用於檢查字元是字串、數字還是特殊字元

在本文中，我們將瞭解一個選單驅動的程式，該程式使用 Java 程式語言 檢查輸入的字元是數字、字串還是特殊字元。我們將使用 switch case 實現此應用程式。

為您展示一些示例

示例 1

Suppose the entered character is ‘a’ then the output should be “Entered character is a String”.

示例 2

Suppose the entered character is ‘1’ then the output should be “Entered character is a number”.

示例 3

Suppose the entered character is ‘$’ then the output should be “Entered character is a Special character”.

語法

要檢查 Java 中的字元是字串、數字還是特殊字元，我們可以使用 isLetter、isDigit 或 isWhitespace 函式。字串由 isLetter 函式檢查，數字由 isDigit 函式檢查，特殊字元由 isLetter、isDigit 和 isWhitespace 函式的組合檢查。

以下是字串函式的語法

Character.isLetter(ob1)

以下是數字函式的語法

Character.isDigit(ob1)

以下是字串函式的語法

(!Character.isDigit(ob1)&& !Character.isLetter(ob1)&& !Character.isWhitespace(ob1))

演算法

步驟 1 - 提示使用者輸入所需的字元。

步驟 2 - 顯示選單。

步驟 3 - 提示使用者輸入他們的選擇。

步驟 4 - 使用 switch case 跳轉到選擇並執行操作。

步驟 5 - 列印結果。

讓我們看看程式以更清楚地瞭解它。

示例

import java.util.*;
public class Main {
   public static void main(String args[]) {
      Scanner sc = new Scanner( System.in );
      System.out.println("Enter a character to check if it's a Number, String or a Special character");
      char ob1 = sc.next().charAt(0);

      System.out.println("Now choose the operation you want to perform from the menu given below. ");

      mainLoop: while (true) {
         Scanner inn = new Scanner( System.in );
         System.out.println("\n***Menu***");
         System.out.println("1. Check if a character is number");
         System.out.println("2. Check if a character is String");
         System.out.println("3. Check if a character is Special character");
         System.out.println("4. Terminate the program");
         System.out.println("Enter action number (1-4): ");
         int command;
         if ( inn.hasNextInt() ) {
            command = inn.nextInt();
            inn.nextLine();
         }
         else {
            System.out.println("\nILLEGAL RESPONSE. YOU MUST ENTER A NUMBER.");
            inn.nextLine();
            continue;
         }
         switch(command) {
            case 1:
            if (Character.isDigit(ob1)) {
               System.out.println("Character is a number!");
            } else {
               System.out.println("Character is not a number!");
            }
            break;
            case 2:
            if (Character.isLetter(ob1)) {
               System.out.println("Character is a String!");
            } else {
               System.out.println("Character is not a String!");
            }
            break;
            case 3:
            if (!Character.isDigit(ob1)
            && !Character.isLetter(ob1)
            && !Character.isWhitespace(ob1)) {
               System.out.println("Character is a Special Character!");
            } else {
               System.out.println("Character is not a Special Character!");
            }
            break;
            case 4:
            System.out.println("Program terminated");
            break mainLoop;
            default:
            System.out.println("Wrong choice!!");
         }

      }

   }
}

輸出

Enter a character to check if it's a Number, String or a Special character
t
Now choose the operation you want to perform from the menu given below.
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
1
Character is not a number!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
3
Character is not a Special Character!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
2
Character is a String!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
$
ILLEGAL RESPONSE. YOU MUST ENTER A NUMBER.
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
1
Character is not a number!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
3
Character is not a Special Character!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
2
Character is a String!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
4
Program terminated

在本文中，我們探討了如何使用選單驅動方法在 Java 中檢查字元是字串、數字還是特殊字元。

更新於: 2024 年 5 月 31 日

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