calculator.java

这是用java写的一个简单的计算器源码

          prekey = key = 2; 
    } 
//'/'操作 
    if (temp == buttonDiv) { 
         switch (prekey) { 
             case 0: 
                 answerd += Double.parseDouble(textAnswer.getText()); 
                 break; 
             case 1: 
                 answerd -= Double.parseDouble(textAnswer.getText()); 
                 break; 
             case 2: 
                 answerd *= Double.parseDouble(textAnswer.getText()); 
                 break; 
             case 3: 
                 if (Double.parseDouble(textAnswer.getText()) == 0) { 
                      textAnswer.setText("除数不能为零"); 
                      clickable = false; 
                 } 
                 else 
                      answerd /= Double.parseDouble(textAnswer.getText()); 
                 break; 
            default: 
                      answerd = Double.parseDouble(textAnswer.getText()); 
         } 
         textAnswer.setText(""); 
         prekey = key = 3; 
      } 
   } 
//'='操作 
   if (temp == buttonEqual && clickable == true) { 
//如果连续按'=',则进行连续运算 
       if (prekey == 5) { 
           if (key == 0) { 
               answerd += vard; 
               textAnswer.setText(df.format(answerd)); 
           } 
           if (key == 1) { 
               answerd -= vard; 
               textAnswer.setText(df.format(answerd)); 
           } 
           if (key == 2) { 
               answerd *= vard; 
               textAnswer.setText(df.format(answerd)); 
           } 
           if (key == 3) { 
               if (Double.parseDouble(textAnswer.getText()) == 0) { 
                    textAnswer.setText("除数不能为零"); 
                    clickable = false; 
               } 
               else { 
                    answerd /= vard; 
                    textAnswer.setText(df.format(answerd)); 
               } 
       } 
    } 
    else { 
         vard = Double.parseDouble(textAnswer.getText()); 
         if (key == 0) { 
              prekey = -1; 
              answerd += Double.parseDouble(textAnswer.getText()); 
              textAnswer.setText(df.format(answerd)); 
         } 
         if (key == 1) { 
              prekey = -1; 
              answerd -= Double.parseDouble(textAnswer.getText()); 
              textAnswer.setText(df.format(answerd)); 
         } 
         if (key == 2) { 
              prekey = -1; 
              answerd *= Double.parseDouble(textAnswer.getText()); 
              textAnswer.setText(df.format(answerd)); 
         } 
         if (key == 3) { 
             prekey = -1; 
             if (Double.parseDouble(textAnswer.getText()) == 0) { 
                  textAnswer.setText("除数不能为零"); 
                  clickable = false; 
             } 
             else { 
                  answerd /= Double.parseDouble(textAnswer.getText()); 
                  textAnswer.setText(df.format(answerd)); 
             } 
         } 
     } 
     prekey = 5; 
  } 
//'%'操作，对第二个操作数除以100 
   if (temp == buttonMod && clickable == true) { 
        if (answerd == 0) { 
             String s = textAnswer.getText(); 
             textAnswer.setText(s); 
        } 
        else { 
             boolean isDot = false; 
             for (int i = 0; i < textAnswer.getText().length(); i++) 
                  if ('.' == textAnswer.getText().charAt(i)) { 
                        isDot = true; 
                        break; 
                  } 
//如果是double数，除100 
             if (isDot == true) { 
                  double dtemp = Double.parseDouble(textAnswer.getText()); 
                  dtemp = dtemp / 100.0; 
                  textAnswer.setText(Double.toString(dtemp)); 
             } 
             else { 
//如果是int数但能被100整除，则去掉末尾两个零 
                  if (Integer.parseInt(textAnswer.getText()) % 100 == 0) { 
                       int itemp = Integer.parseInt(textAnswer.getText()); 
                       itemp /= 100; 
                       textAnswer.setText(Integer.toString(itemp)); 
                  } 
//如果是int数，但不能被100整除，则按double数处理 
                  else { 
                        double dtemp = Double.parseDouble(textAnswer.getText()); 
                        dtemp = dtemp / 100.0; 
                        textAnswer.setText(Double.toString(dtemp)); 
                  } 
            } 
       } 
    } 
//开根号运算 
    if (temp == buttonSqrt && clickable == true) { 
         String s = textAnswer.getText(); 
         if (s.charAt(0) == '-') { 
              textAnswer.setText("负数不能开根号"); 
              clickable = false; 
         } 
         else 
              textAnswer.setText(Double.toString(java.lang.Math.sqrt(Double. 
         parseDouble(textAnswer.getText())))); 
    }  
//倒数运算 
    if (temp == buttonDao && clickable == true) { 
         if (textAnswer.getText().charAt(0) == '0' && 
              textAnswer.getText().length() == 1) { 
              textAnswer.setText("零不能求倒数"); 
              clickable = false; 
         } 
         else { 
              boolean isDec = true; 
              int i, j, k; 
              String s = Double.toString(1 / Double.parseDouble(textAnswer.getText())); 
              for (i = 0; i < s.length(); i++) 
                    if (s.charAt(i) == '.') 
                         break; 
              for (j = i + 1; j < s.length(); j++) 
                    if (s.charAt(j) != '0') { 
                         isDec = false; 
                    break; 
        } 
        if (isDec == true) { 
             String stemp = ""; 
             for (k = 0; k < i; k++) 
                   stemp += s.charAt(k); 
             textAnswer.setText(stemp); 
        } 
        else 
             textAnswer.setText(s); 
    } 
 } 
//按下'+/-'按钮时处理 
    if (temp == buttonAddAndSub && clickable == true) { 
         boolean isNumber = true; 
         String s = textAnswer.getText(); 
         for (int i = 0; i < s.length(); i++) 
               if (! (s.charAt(i) >= '0' && s.charAt(i) <= '9' || s.charAt(i) == '.' || 
                      s.charAt(i) == '-')) { 
                    isNumber = false; 
                    break; 
               } 
         if (isNumber == true) { 
//如果当前字符串首字母有'-'号,代表现在是个负数,再按下时,则将首符号去掉 
              if (s.charAt(0) == '-') { 
                   textAnswer.setText(""); 
              for (int i = 1; i < s.length(); i++) { 
                    char a = s.charAt(i); 
                    textAnswer.setText(textAnswer.getText() + a); 
              } 
          } 
//如果当前字符串第一个字符不是符号，则添加一个符号在首字母处 
          else 
              textAnswer.setText('-' + s); 
    } 
    } 
//计算器有关内存操作 
//'MC'的操作，将内存清0 
    if (temp == buttonMC && clickable == true) { 
         memoryd = memoryi = 0; 
         textMemory.setText(""); 
    } 
//'MS'的操作，将当前文本框内容保存入内存，显示'M' 
    if (temp == buttonMS && clickable == true) { 
         boolean isDot = false; 
         textMemory.setText(" M"); 
         for (int i = 0; i < textAnswer.getText().length(); i++) 
               if ('.' == textAnswer.getText().charAt(i)) { 
                    isDot = true; 
                    break; 
               } 
//如果是double,则存入memoryd(double存储器) 
         if (isDot == true) { 
              memoryd = Double.parseDouble(textAnswer.getText()); 
              memoryi = 0; //保证存储器中存放最新的值 
         } 
//如果是int,则存入memoryi(int存储器) 
         else { 
              memoryi = Integer.parseInt(textAnswer.getText()); 
              memoryd = 0; //保证存储器中存放最新的值 
         } 
    } 
//'MR'的操作，将存储器中的信息输出 
    if (temp == buttonMR && clickable == true) { 
         if (memoryd != 0) 
              textAnswer.setText(Double.toString(memoryd)); 
         if (memoryi != 0) 
              textAnswer.setText(Integer.toString(memoryi)); 
    } 
//'M+'的功能，将当前文本框里的数据和存储器中数据相加后，再存入存储器 
    if (temp == buttonMAdd && clickable == true) { 
         boolean isDot = false; 
         for (int i = 0; i < textAnswer.getText().length(); i++) 
               if ('.' == textAnswer.getText().charAt(i)) { 
                     isDot = true; 
                     break; 
               } 
         if (memoryi != 0) { //存储中是一个int型数 
              if (isDot == false) //被加数是一个int型数 
                   memoryi += Integer.parseInt(textAnswer.getText()); 
              else { //被加数是一个double型数，则将int存储器中数传入double存储器与当前数相加，int存储器清零 
                   memoryd = memoryi + Double.parseDouble(textAnswer.getText()); 
                   memoryi = 0; 
         } 
    } 
    else 
         memoryd += Double.parseDouble(textAnswer.getText()); 
    } 
//按下'Backspace'键，利用循环将当前字符串中的最后一个字母删除 
    if (temp == buttonBk && clickable == true) { 
         String s = textAnswer.getText(); 
         textAnswer.setText(""); 
         for (int i = 0; i < s.length() - 1; i++) { 
               char a = s.charAt(i); 
               textAnswer.setText(textAnswer.getText() + a); 
         } 
    } 
//按下'CE'按钮，将当前文本框内数据清除 
    if (temp == buttonCe) { 
         textAnswer.setText(""); 
         clickable = true; 
    } 
//按下'C'按钮，文本框内数据清除，同时var,answer清0 
    if (temp == buttonC) { 
         vard = answerd = 0; 
         textAnswer.setText(""); 
         clickable = true; 
    } 
//按下'复制'菜单栏 
    if (temp == copyItem) { 
         copy = textAnswer.getText(); 
    } 
//按下'粘贴'菜单栏 
    if (temp == pasteItem) { 
         textAnswer.setText(copy); 
    } 
    if (temp == sItem) { 
         JOptionPane.showMessageDialog(panel, "当前是标准型计算器，\n科学型计算器有待更新。"); 
    } 
//按下'帮助主题'菜单栏 
    if (temp == topHelp) { 
         JOptionPane.showMessageDialog(panel, scrollHelp); 
    } 
//按下'数字分组'菜单栏 
    if (temp == numberGroup) { 
         if (numberGroup.getText().compareTo(" 数字分组(I)") == 0) 
              numberGroup.setText("√数字分组(I)"); 
         else 
              numberGroup.setText(" 数字分组(I)"); 
    } 
//按下'关于'菜单栏 
    if (temp == aboutCal) { 
         JOptionPane.showMessageDialog(panel, "计算器1.00版\n开发者：楼竞"); 
    } 
    } 
//输入中如果有操作非法，比如按下两次'+'，捕获异常 
    catch (Exception e) { 
            textAnswer.setText("操作非法"); 
            clickable = false; 
    } 
} 
//主函数 
    public static void main(String args[]) { 
           new Calculator(); 
    } 
}