# Java 程序：乘以兩個數字 > 原文： [https://beginnersbook.com/2017/09/java-program-to-multiply-two-numbers/](https://beginnersbook.com/2017/09/java-program-to-multiply-two-numbers/) 當您開始學習 [java 編程](https://beginnersbook.com/java-tutorial-for-beginners-with-examples/)時，您在作業中遇到了這些類型的問題。這里我們將看到兩個 Java 程序，第一個程序接受兩個整數（由用戶輸入）并顯示這些數字的乘積。第二個程序采用任意兩個數字（可以是整數或浮點數）并顯示結果。 ## 示例 1：讀取兩個整數并打印它們的產品 該程序要求用戶輸入兩個整數并顯示產品。要了解如何使用掃描儀獲取用戶輸入，請檢查此程序：[程序從系統輸入](https://beginnersbook.com/2017/09/java-program-to-read-integer-value-from-the-standard-input/)讀取整數。 ```java import java.util.Scanner; public class Demo { public static void main(String[] args) { /* This reads the input provided by user * using keyboard */ Scanner scan = new Scanner(System.in); System.out.print("Enter first number: "); // This method reads the number provided using keyboard int num1 = scan.nextInt(); System.out.print("Enter second number: "); int num2 = scan.nextInt(); // Closing Scanner after the use scan.close(); // Calculating product of two numbers int product = num1*num2; // Displaying the multiplication result System.out.println("輸出： "+product); } } ``` **輸出：** ```java Enter first number: 15 Enter second number: 6 輸出： 90 ``` ## 示例 2：讀取兩個整數或浮點數并顯示乘法 在上面的程序中，我們只能整數。如果我們想計算兩個浮點數的乘積怎么辦？此程序允許您輸入浮點數并計算產品。 這里我們使用[數據類型](https://beginnersbook.com/2017/08/data-types-in-java/) double 作為數字，這樣你就可以輸入整數和浮點數。 ```java import java.util.Scanner; public class Demo { public static void main(String[] args) { /* This reads the input provided by user * using keyboard */ Scanner scan = new Scanner(System.in); System.out.print("Enter first number: "); // This method reads the number provided using keyboard double num1 = scan.nextDouble(); System.out.print("Enter second number: "); double num2 = scan.nextDouble(); // Closing Scanner after the use scan.close(); // Calculating product of two numbers double product = num1*num2; // Displaying the multiplication result System.out.println("輸出： "+product); } } ``` **輸出：** ```java Enter first number: 1.5 Enter second number: 2.5 輸出： 3.75 ```