两数求和--用对话框

[java]代码库

// 两数相加

import javax.swing.JOptionPane;  // import class JOptionPane

public class Addition {
   public static void main( String args[] )
   {
      String firstNumber,   // first string entered by user
             secondNumber;  // second string entered by user
      double number1,          // first number to add
          number2,          // second number to add
          sum;              // sum of number1 and number2

      // 从对话框中输入第一个数；对话框中输入的都是string类型的值
      firstNumber =
         JOptionPane.showInputDialog( "请输入第个数：" );  //对话框

      // 从对话框中输入第二个数
      secondNumber =
         JOptionPane.showInputDialog( "Enter second integer" );  //对话框

      // 将string类型的数据强制转换为int类型
      number1 = Double.parseDouble( firstNumber ); 
      number2 = Double.parseDouble( secondNumber );

      // 两数相加
      sum = number1 + number2;

      // 输出结果对话框，后边两个参数与标题框有关，可有可无；
      JOptionPane.showMessageDialog(
    	         null, "The sum is " + sum, "Results",
    	         JOptionPane.PLAIN_MESSAGE );
      System.exit( 0 );   
   }
}

[代码运行效果截图]