2.15
// An addition program
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
int number1, // first number to add
number2, // second number to add
sum; // sum of number1 and number2
// read in first number from user as a string
firstNumber =
JOptionPane.showInputDialog( "Enter first integer" );
// read in second number from user as a string
secondNumber =
JOptionPane.showInputDialog( "Enter second integer" );
// convert numbers from type String to type int
number1 = Integer.parseInt( firstNumber );
number2 = Integer.parseInt( secondNumber );
// add the numbers
sum = number1 + number2;
// display the results
JOptionPane.showMessageDialog(
null, "The sum is " + sum, "Results",
JOptionPane.PLAIN_MESSAGE );
System.exit( 0 ); // terminate the program
}
}
这个程序弹出对话框获取用户输入的两个整数,然后将其相加并显示结果。程序首先导入了JOptionPane类,该类提供了弹出对话框的功能,用于与用户进行交互。然后,在main方法中,定义了几个变量:firstNumber和secondNumber用于存储用户输入的两个整数(以字符串形式),number1和number2用于存储将字符串转换为整数后的结果,sum用于存储两个整数的和。接下来,使用JOptionPane.showInputDialog方法弹出对话框,提示用户输入第一个整数和第二个整数,并将用户输入的结果存储到firstNumber和secondNumber中。然后,使用Integer.parseInt方法将firstNumber和secondNumber转换为整数类型,并将结果存储到number1和number2中。接着,将number1和number2相加,将结果存储到sum中。最后,使用JOptionPane.showMessageDialog方法弹出对话框,显示计算结果sum。