极客笔记Java 菜单驱动程序检查数字类型
在Java中，我们有原始数值数据类型，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的数字。这些数值数据类型允许我们根据它们的范围表示不同的整数和实数，因为每个具体的数据类型都有它的下限和上限。
以下是6种原始数值数据类型：
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。
为了向您展示一些示例
示例-1
Suppose we have taken an integer type of value i.e. 222222 then it must show “number entered is a valid integer”.
示例-2
Suppose we have taken a double type of value i.e 120.0 then it must show “number entered is a valid double”.
示例-3
Suppose we have taken a float type of value i.e 2.1 then it must show “number entered is a valid float”.
示例-4
Suppose we have taken a byte type of value i.e 23 then it must show “number entered is a valid byte”.
示例-5
Suppose we have taken a short type of value i.e 32,765 then it must show “number entered is a valid short”.
示例-6
Suppose we have taken a long type of value i.e 222222222222 then it must show “number entered is a valid long”.
语法
若要检查数字的类型，我们将检查其数据类型。如果数据类型匹配，则结果将为正；否则为负。我们有一个名为 hasNextData_Type 的函数用于检查它。
以下是检查“整数数据类型”的语法 –
hasNextInt()
以下是检查“double数据类型”的语法 –
hasNextDouble()
以下是检查“float数据类型”的语法-
hasNextFloat()
以下是检查“byte数据类型”的语法的格式 –
hasNextByte()
以下是检查“short”数据类型的语法：
hasNextShort()
以下是检查“long数据类型”的语法 –
hasNextLong()
步骤
步骤-1 - 要求用户输入选择。
步骤-2 - 显示菜单。
步骤-3 - 要求用户输入数据。
步骤-4 - 使用switch case语句来执行选择并进行操作。
步骤-5 - 打印结果。
让我们来看一个程序以更清楚地理解它。
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!!");
}
}
}
}
输出
***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
在这篇文章中，我们通过使用菜单驱动的方法来探讨了如何在Java中检查数字的类型。