学习Java第二天

• 单词含义
  import导入、public公开、class类、static静态、string字符串、void空的、main类的主方法
• 输出语句
  System.out.println();
  int整数、double小数
• 快捷键
  alt+/是eclipse（IDE工具）错误帮助
  ctrl+1是调出错误帮助选项框
  ctrl+F11是编译解释快捷键

基本运算程序

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import javax.swing.JOptionPane;

public class Calc {
        public static void main(String[] args) {
        double num1 = 999;
        double num2 = 777;
        System.out.println(num1 + "+" + num2 + "=" + (num1 + num2));
        System.out.println(num1 + "-" + num2 + "=" + (num1 - num2));
        System.out.println(num1 + "*" + num2 + "=" + (num1 * num2));
        System.out.println(num1 + "/" + num2 + "=" + (num1 / num2));

        JOptionPane.showMessageDialog(null,num1 + "+" + num2 + "=" + (num1 + num2));
        JOptionPane.showMessageDialog(null,num1 + "-" + num2 + "=" + (num1 - num2));
        JOptionPane.showMessageDialog(null,num1 + "*" + num2 + "=" + (num1 * num2));
        JOptionPane.showMessageDialog(null,num1 + "/" + num2 + "=" + (num1 / num2));
        System.exit(0);
    }
}