expcalframe.java

数值计算,表达式求值, 如计算3 + 2 * ( 3 + 2) / 5 + 8 + Sin( pi() / 180 * 30 ) + 1 + 2 ^ 10, 可自定义函数, 采用递归算法

package expresscalculate;

import java.awt.*;
import javax.swing.*;
import com.borland.jbcl.layout.XYLayout;
import com.borland.jbcl.layout.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.util.*;
import java.lang.Math.*;

public class ExpCalFrame
    extends JFrame {
  JPanel contentPane;
  XYLayout xYLayout1 = new XYLayout();
  JTextField jtfExp = new JTextField();
  JButton btnCal = new JButton();
  JTextField jtfResult = new JTextField();
  javax.swing.JLabel jLabel1 = new JLabel();
  javax.swing.JLabel jLabel2 = new JLabel();
  public ExpCalFrame() {
    try {
      setDefaultCloseOperation(EXIT_ON_CLOSE);
      jbInit();
    }
    catch (Exception exception) {
      exception.printStackTrace();
    }
  }

  /**
   * Component initialization.
   *
   * @throws java.lang.Exception
   */
  private void jbInit() throws Exception {
    contentPane = (JPanel) getContentPane();
    contentPane.setLayout(xYLayout1);
    setSize(new Dimension(500, 300));
    setTitle("表达式计算");
    jtfExp.setText(
        "3 + 2 * ( 3 + 2) / 5 + 8 + Sin( pi() / 180 * 30 ) + 1 + 2 ^ 10");
    btnCal.setIcon(null);
    btnCal.setText("计算");
    btnCal.addActionListener(new ExpCalFrame_btnCal_actionAdapter(this));
    jtfResult.setText("");
    jLabel1.setText("表达式");
    jLabel2.setText("值");
    contentPane.add(jtfExp, new XYConstraints(9, 36, 472, 27));
    contentPane.add(jtfResult, new XYConstraints(11, 99, 168, 28));
    contentPane.add(btnCal, new XYConstraints(223, 169, 94, -1));
    contentPane.add(jLabel1, new XYConstraints(10, 13, -1, -1));
    contentPane.add(jLabel2, new XYConstraints(10, 81, -1, -1));

    Font fontSet = new Font("宋体", Font.PLAIN, 12);
    setControlFont(contentPane, fontSet);
  }

  /**
   * 设置控件字体(递归)
   *
   * @param component Component  控件
   * @param fontSet Font  要设成的字体
   */
  public void setControlFont(Component component, Font fontSet) {
    //System.out.println("设置字体" + component.getClass().getName());
    if (component instanceof Container) {
      Component c[] = ( (Container) component).getComponents();
      for (int i = 0, n = c.length; i < n; i++) {
        c[i].setFont(fontSet);
        setControlFont(c[i], fontSet);
      }
    }
  }


  public void btnCal_actionPerformed(ActionEvent e) {

    String strResult = "";
    double dResult = CalculateExp(jtfExp.getText());
    strResult = String.valueOf(dResult);
    jtfResult.setText(strResult);
  }

  /**计算表达式*/
  public double CalculateExp(String sExp) {
    System.out.println(sExp);
    double[] a = new double[10];
    char[] b = new char[10];
    int m, n, iLeftBracket, iRightBracket, i;
    String strNum, strSub;
    boolean bEnd, bFlag, bNotEqu;
    String s;
    char[] sarr;
    String strOpr = "+-*/()^";

    s = sExp;
    s = StrDelBlank(s);
    s = ReplaceFunction(s);
    sarr = s.toCharArray();
    if (s.length() == 0) {
      return 0;
    }

    if (!(CheckExpCharValid(s))) {
      return 0;
    }

    if (!(CheckExpBracket(s))) {
      return 0;
    }

    if ((sarr[0] == '+') || (sarr[0] == '-')) {
      if (sarr.length == 1) {
        JOptionPane.showMessageDialog(this, "表达式有误! 表达式:" + s);
        System.exit(0);
      }
      if (sarr[1] == '(') {
        s = s.substring(1);
        return CalculateExp("(-1)*" + s);
      }

      for (i = 1; i < sarr.length; i ++) {
        if (strOpr.indexOf(sarr[i]) > -1) {
          s = "(" + s.substring(0, i) + ")" + s.substring(i);
          return CalculateExp(s);
        }
      }
      return Double.parseDouble(s);
    }

    for (i = 0; i < 10; i ++) {
      a[i] = 0;
      b[i] = ' ';
    }

    i = 0;
    m = -1;
    n = -1;
    while (i < sarr.length) {
      switch (sarr[i]) {
        case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': {
          bEnd = false;
          strNum = "";
          while (!bEnd) {
            if (i == sarr.length - 1) {
              if (strOpr.indexOf(sarr[i]) < 0) {
                strNum = strNum + sarr[i];
                m = m + 1;
                try {
                  a[m] = Double.parseDouble(strNum);
                }
                catch (Exception e){
                  JOptionPane.showMessageDialog(this, "数值表达式错误:" + strNum + "; " + e.getMessage());
                  System.exit(0);
                }
                if (m != n + 1) {
                  JOptionPane.showMessageDialog(this, "表达式有误!操作符,操作不匹配!" + s);
                  System.exit(0);
                }
                i = i + 1;
              }
              bEnd = true;
            }
            else {
              if (strOpr.indexOf(sarr[i]) > -1) {
                bEnd = true;
              }
              else {
                strNum = strNum + sarr[i];
                i = i + 1;
              }

              if (bEnd ) {
                m = m + 1;
                try {
                  a[m] = Double.parseDouble(strNum);
                }
                catch (Exception e){
                  JOptionPane.showMessageDialog(this, "数值表达式错误:" + strNum + "; " + e.getMessage());
                  System.exit(0);
                }
                if (m != n + 1) {
                  JOptionPane.showMessageDialog(this, "表达式有误!操作符,操作不匹配!" + s);
                  System.exit(0);
                }
              }
            }
          }
          break;
        }

        case '+': case '-': case '*': case '/': case '^': {
          n = n + 1;
          b[n] = sarr[i];
          if (m != n ) {
            JOptionPane.showMessageDialog(this, "表达式有误!操作符,操作不匹配!" + s);
            System.exit(0);
          }

          i = i + 1;
          break;
        }

        case '(': {
          iLeftBracket = 1;
          iRightBracket = 0;
          strSub = "";
          bNotEqu = true;
          i = i + 1;
          while (bNotEqu && (i < sarr.length)) {
            strSub = strSub + sarr[i];
            if (sarr[i] == '(') {
              iLeftBracket = iLeftBracket + 1;
            }
            if (sarr[i] == ')') {
              iRightBracket = iRightBracket + 1;
            }
            if (iLeftBracket == iRightBracket) {
              bNotEqu = false;
            }
            i = i + 1;
          }

          if (bNotEqu) {
            JOptionPane.showMessageDialog(this, "表达式缺右括号!");
            System.exit(0);
          }

          if (strSub.length() > 1) {
            strSub = strSub.substring(0, strSub.length() - 1);
          }

          m = m + 1;
          a[m] = CalculateExp(strSub);
          if (m != n + 1) {
            JOptionPane.showMessageDialog(this, "表达式有误!操作符,操作不匹配!" + s);
            System.exit(0);
          }

          break;
        }

        case ')': {
          JOptionPane.showMessageDialog(this, "表达式缺左括号!");
          System.exit(0);
          break;
        }

        default: {
          JOptionPane.showMessageDialog(this, "表达式:" + s + " 位置:" + String.valueOf(i) + " 处的 " + sarr[i]);
          System.exit(0);
          break;
        }
      }

      if (m == n + 1 && n > -1) {
        if (b[n] == '*' || b[n] == '/' || b[n] == '^') {
          a[m-1] = CalculateSimple(a[m-1], a[m], b[n]);
          a[m] = 0;
          b[n] = ' ';
          m = m - 1;
          n = n - 1;
        }
      }

      bFlag = true;
      while (bFlag) {
        if (m != -1 && m == n && m != 0 && (b[n] == '+' || b[n] == '-')) {
          a[m - 1] = CalculateSimple(a[m - 1], a[m], b[n - 1]);
          a[m] = 0;
          m = m - 1;
          n = n - 1;