# Java 程序：计算三角面积

> 原文： [https://beginnersbook.com/2014/01/java-program-to-calculate-area-of-triangle/](https://beginnersbook.com/2014/01/java-program-to-calculate-area-of-triangle/)

在这里，我们将看到如何计算三角形的面积。我们将看到以下两个程序：

1）程序 1：提示用户输入三角形的基本宽度和高度。

2）程序 2：无用户交互：程序本身指定了宽度和高度。

**计划 1：**

```java
/**
 * @author: BeginnersBook.com
 * @description: Program to Calculate area of Triangle in Java
 * with user interaction. Program will prompt user to enter the 
 * base width and height of the triangle.
 */
import java.util.Scanner;
class AreaTriangleDemo {
   public static void main(String args[]) {   
      Scanner scanner = new Scanner(System.in);

      System.out.println("Enter the width of the Triangle:");
      double base = scanner.nextDouble();

      System.out.println("Enter the height of the Triangle:");
      double height = scanner.nextDouble();

      //Area = (width*height)/2
      double area = (base* height)/2;
      System.out.println("Area of Triangle is: " + area);      
   }
}
```

输出：

```java
Enter the width of the Triangle:
2
Enter the height of the Triangle:
2
Area of Triangle is: 2.0
```

**计划 2：**

```java
/**
 * @author: BeginnersBook.com
 * @description: Program to Calculate area of Triangle
 * with no user interaction.
 */
class AreaTriangleDemo2 {
   public static void main(String args[]) {   
      double base = 20.0;
      double height = 110.5;
      double area = (base* height)/2;
      System.out.println("Area of Triangle is: " + area);      
    }
}
```

输出：

```java
Area of Triangle is: 1105.0
```