计算器核心代码

/**
  * 计算器的核心逻辑实现
  */
 private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
  // TODO add your handling code here:
  float num1 = Float.parseFloat(this.jTextField1.getText());
  float num2 = Float.parseFloat(this.jTextField2.getText());
  int flag = jComboBox1.getSelectedIndex();
  float result = 0.0f;

  switch (flag) {
  case 0:
   result = num1 + num2;
   this.jTextField3.setText(Float.toString(result));
   break;
  case 1:
   result = num1 - num2;
   this.jTextField3.setText(Float.toString(result));
   break;
  case 2:
   result = num1 * num2;
   this.jTextField3.setText(Float.toString(result));
   break;
  case 3:
   result = num1 / num2;
   this.jTextField3.setText(Float.toString(result));
   break;
  }
 }