Java菜单驱动程序以检查数字类型

在Java中，我们有原始的数值数据类型，用于表示短整型、字节型、整型、长整型、浮点型和双精度浮点型。这些数值数据类型允许我们根据它们的范围来表示不同的整数和实数，因为每个特定的数据类型都有它的下限和上限。

Below are the 6 primitive numeric data types

byte: Range -128 to 127 (Size 1 byte)
short: Range -32,768 to 32,767 (Size 2 bytes)
int: Range -2,147,483,648 to 2,147,483,647 (Size 4 bytes)
long: Range -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (8 bytes)
float: Range 6 to 7 decimal digits for Fractional Numbers (Size 4 bytes)
double: Range 15 decimal digits for Fractional Numbers (Size 8 bytes)

在本文中，我们将看到如何通过使用Java编程语言来检查数字的类型。我们将使用switch case来实现该应用程序。

展示一些实例给你看

Instance-1

Suppose we have taken an integer type of value i.e. 222222 then it must show “number entered is a valid integer”.

实例-2

Suppose we have taken a double type of value i.e 120.0 then it must show “number entered is a valid double”.

Instance-3

实例-3

Suppose we have taken a float type of value i.e 2.1 then it must show “number entered is a valid float”.

Instance-4

Suppose we have taken a byte type of value i.e 23 then it must show “number entered is a valid byte”.

Instance-5

实例-5

Suppose we have taken a short type of value i.e 32,765 then it must show “number entered is a valid short”.

Instance-6

Suppose we have taken a long type of value i.e 222222222222 then it must show “number entered is a valid long”.

Syntax

To check the type of number we will check its datatype. If the datatype matches then the result will be positive otherwise negative. To check it we have a function called hasNextData_Type.

以下是检查“整数数据类型”的语法：

hasNextInt()

Following is the syntax to check “double datatype” −

hasNextDouble()

以下是检查“浮点数据类型”的语法：

hasNextFloat()

Following is the syntax to check “byte datatype” −

hasNextByte()

以下是检查“short数据类型”的语法 -

hasNextShort()

Following is the syntax to check “long datatype” −

hasNextLong()

Algorithm

Step-1 − Ask the user to enter their choice.

第二步 - 显示菜单。

步骤-3 − 要求用户输入数据。

第四步 - 使用switch case语句进行选择并执行操作。

步骤-5 - 打印结果。

Let’s see the program to understand it clearly.

Example

示例

import java.util.*;
public class Main{
   public static void main(String args[]){
      mainLoop: while (true) {
         Scanner sc = new Scanner( System.in );
         System.out.println("\n***Menu***");
         System.out.println("1. Check for Integer");
         System.out.println("2. Check for Double");
         System.out.println("3. Check for Float");
         System.out.println("4. Check for Byte");
         System.out.println("5. Check for Short");
         System.out.println("6. Check for Long");
         System.out.println("7. Terminate the program");
         System.out.println("Enter action number (1-7): ");
         int command = sc.nextInt();
         switch(command) {
            case 1:
            int input = 0;
            System.out.println("Enter an integer for its validation");
            if(sc.hasNextInt()) {
               input = sc.nextInt();
               System.out.println(input+" is a valid Integer");
            }
            else{
               System.out.println("It is not a valid Integer");
            }
            break;
            case 2:
            double input1 = 0;
            System.out.println("Enter a Double for its validation");
            if(sc.hasNextDouble()) {
               input1 = sc.nextDouble();
               System.out.println(input1+" is a valid Double");
            }
            else {
               System.out.println("It is not a valid Double");
            }
            break;
            case 3:
            float input2;
            System.out.println("Enter a Float for its validation");
            if(sc.hasNextFloat()) {
               input2 = sc.nextFloat();
               System.out.println(input2+" is a valid Float");
            }
            else{
               System.out.println("It is not a valid Float");
            }
            break;
            case 4:
            byte input3 = 0;
            System.out.println("Enter a Byte for its validation");
            if(sc.hasNextByte()) {
               input3 = sc.nextByte();
               System.out.println(input3+" is a valid Byte");
            }
            else{
               System.out.println("It is not a valid Byte");
            }
            break;
            case 5:
            short input4 = 0;
            System.out.println("Enter a Short for its validation");
            if(sc.hasNextShort()) {
               input4 = sc.nextShort();
               System.out.println(input4+" is a valid Short");
            }
            else{
               System.out.println("It is not a valid Short");
            }

            break;
            case 6:
            long input5 = 0;
               System.out.println("Enter a Short for its validation");
               if(sc.hasNextLong()) {
                  input5 = sc.nextLong();
                  System.out.println(input5+" is a valid Long");
               }
               else{
                  System.out.println("It is not a valid Long");
               }
               break;
               case 7:
               System.out.println("Program terminated");
               break mainLoop;
               default:
               System.out.println("Wrong choice!!");
         }
      }
   }
}

Output

***Menu***
1. Check for Integer
2. Check for Double
3. Check for Float
4. Check for Byte
5. Check for Short
6. Check for Long
7. Terminate the program
Enter action number (1-7):
1
Enter an integer for its validation
22222
22222 is a valid Integer

***Menu***
1. Check for Integer
2. Check for Double
3. Check for Float
4. Check for Byte
5. Check for Short
6. Check for Long
7. Terminate the program
Enter action number (1-7):
2
Enter a Double for its validation
2.4
2.4 is a valid Double

***Menu***
1. Check for Integer
2. Check for Double
3. Check for Float
4. Check for Byte
5. Check for Short
6. Check for Long
7. Terminate the program
Enter action number (1-7):
3
Enter a Float for its validation
2.5
2.5 is a valid Float

***Menu***
1. Check for Integer
2. Check for Double
3. Check for Float
4. Check for Byte
5. Check for Short
6. Check for Long
7. Terminate the program
Enter action number (1-7):
4
Enter a Byte for its validation
123
123 is a valid Byte

***Menu***
1. Check for Integer
2. Check for Double
3. Check for Float
4. Check for Byte
5. Check for Short
6. Check for Long
7. Terminate the program
Enter action number (1-7):
5
Enter a Short for its validation
1234
1234 is a valid Short

***Menu***
1. Check for Integer
2. Check for Double
3. Check for Float
4. Check for Byte
5. Check for Short
6. Check for Long
7. Terminate the program
Enter action number (1-7):
6
Enter a Short for its validation
345
345 is a valid Long

***Menu***
1. Check for Integer
2. Check for Double
3. Check for Float
4. Check for Byte
5. Check for Short
6. Check for Long
7. Terminate the program
Enter action number (1-7):
7
Program terminated

在本文中，我们探讨了如何通过使用菜单驱动方法来检查Java中的数字类型。

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