用java编写一个简易的计算器代码复习课程.doc

用java编写一个简易的计算器代码

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import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

/*使用java 语言开发一个简易计算器
*
*
*/
public class TestJsq extends JFrame implements ActionListener, KeyListener {
private JTextField jtf;
private JButton jb_bk, jb_ce, jb_c;
private String xs = "";
private double sum = 0;
private int fh;

public static void main(String[] args) {
new TestJsq().creatCUI();

}

public void creatCUI() {
JFrame jf = new JFrame();
jf.setTitle("计算器");
jtf = new JTextField("0.");
jtf.setHorizontalAlignment(JTextField.RIGHT);
jf.add(jtf, BorderLayout.NORTH);
JPanel jp_main = new JPanel(new BorderLayout());
jf.add(jp_main);
JPanel jp1 = new JPanel(new GridLayout(1, 3, 1, 1));
jb_bk = new JButton("Backspace");
jb_bk.setForeground(Color.RED);
jb_bk.addActionListener(this);
jb_ce = new JButton("CE");
jb_ce.setForegroundColor.RED);
jb_ce.addActionListener(this);
jb_c = new JButton("C");
jb_c.setForeground(Color.RED);
jb_c.addActionListener(this);
jp1.add(jb_bk);
jp1.add(jb_ce);
jp1.add(jb_c);
jp_main.add(jp1, BorderLayout.NORTH);
JPanel jp2 = new JPanel(new GridLayout(4, 5, 1, 1));
String str[] = { "7", "8", "9", "/", "sqrt", "4", "5", "6", "*", "%",
"1", "2", "3", "-", "1/x", "0", "+/-", ".", "+", "=" };
for (int i = 0; i < 20; i++) {
JButton jb = new JButton(str[i]);
jb.addActionListener(this);
jb.setForeground(Color.blue);
if (i == 3 || i == 8 || i == 13 || i == 18 || i == 19) {
jb.setForeground(Color.RED);
}
jp2.add(jb);
}
jp_main.add(jp2, BorderLayout.CENTER);
jf.setResizable(false);
jf.setBounds(50, 50, 350, 350);
jf.setVisible(true);

}

@Override
public void actionPerformed(ActionEvent e) {
String s = egetActionCommand();
if (s.equals("CE") || s.equals("C")) {
xs = "";
jtf.setText("0.");

} else if (s.equals("Backspace")) {
String str = xs.substring(0, xs.length() - 1);
xs = str;
jtf.setText(xs);

} else if (s.equals("7") || s.equals("8") || s.equals("9")
|| s.equals("4") || s.equals("5") || s.equals("6")
|| s.equals("1") || s.equals("2") || s.equals("3")
|| s.equals("0") || s.equals(".")) {
xs = xs + s;
jtf.setText(xs);

} else if (s.equals("+/-")) {
double x = Double.parseDouble(xs);
xs="" + (-x);
jtf.setText(xs);

} else if (s.equals("/")) {
fh = 4;
int point = xs.indexOf(".");
if (point != -1) {
String strt = xs.substring(0, point);
String z = xs.substring(point + 1, xs.length());
int z_num = z.length();
sum = Integer.decode(strt) + (double) (Integer.decode(z))
/ (10 * z_num);
} else {
sum = Integer.decode(xs);
}
xs = "";
jtf.setText(null);

} else if (s.equals("*")) {
fh = 3;
int point = xs.indexOf(".");
if (point != -1) {
String strt = xs.substring(0, point);
String z = xs.substring(point + 1, xs.length());
int z_num = z.length();
sum = Integer.decode(strt) + (double) (Integer.decode(z))
/ (10 * z_num);
} else {
sum = Integer.decode(xs);
}
xs = "";
jtf.setText(null);

} else if (s.equals("-")) {
fh = 2;
int point = xs.indexOf(".");
if (point != -1) {
String strt = xs.substring(0, point);
String z = xs.substring(point + 1, xs.length());
int z_num = z.length();

sum = Integer.decode(strt) + (double) (Integer.decode(z))
/ (10 * z_num);

} else {
sum = Integer.decode(xs);

}
xs = "";
jtf.setText(null);

} else if (s.equals("+")) {
fh = 1;
int point = xs.indexOf(".");
if (point != -1) {
String strt = xs.substring(0, point);
String z = xs.substring(point + 1, xs.length());
int z_num = z.length();

sum = Integer.decode(strt) + (double) (Integer.decode(z))
/ (10 * z_num);

} else {
sum = Integer.decode(xs);

}
xs = "";
jtf.setText(null);

} else if (s.equals("sqrt")) {
double x = Double.parseDouble(xs);
double x1 = Math.sqrt(x);
xs = x1 + "";
jtf.setText(xs);

} else if (s.equals("%")) {
double x = Double.parseDouble(xs);
x=0.01 * x*x;
xs=x+"";
jtf.setText(xs);

} else if (s.equals("1/x")) {
if (xs == "0") {
jtf.setText("除数不能为0");
} else {
double x = Double.parseDouble(xs);
double x1 = 1 / x;
xs = x1 + "";
jtf.setText(String.valueOf(xs));
}

} else if (s.equals("=")) {
if (fh != 0) {
switch (fh) {
case 1:
int point1 = xs.indexOf(".");
if (point1 != -1) {
String s1 = xs.substring(0, point1);
String z1 = xs.substring(point1 + 1, xs.length());
int z1_num = z1.length();
xs = "";
double ss1 = Integer.decode(s1)
+ (double) Integer.decode(z1) / (10 * z1_num);
sum = sum + ss1;
} else {
sum = sum + Integer.decode(xs);
xs = "";
}
fh = 0;
break;
case 2:
int point2 = xs.indexOf(".");
if (point2 != -1) {
String s2 = xs.substring(0, point2);
String z2 = xs.substring(point2 + 1, xs.length());
int z2_num = z2.length();
xs = "";
double ss2 = Integer.decode(s2)
+ (double) Integer.decode(z2) / (10 * z2_num);
sum = sum - ss2;
} else {
sum = sum Integer.decode(xs);
xs = "";
}
fh = 0;
break;
case 3:
int point3 = xs.indexOf(".");
if (point3 != -1) {
String s3 = xs.substring(0, point3);
String z3 = xs.substring(point3 + 1, xs.length());
int z1_num = z3.length();
xs = "";
double s4 = Integer.decode(s3)
+ (double) Integer.decode(z3) / (10 * z1_num);
sum = sum * s4;
} else {
sum = sum * Integer.decode(xs);
xs = "";
}
fh = 0;
break;
case 4:
int point4 = xs.indexOf(".");
if (point4 != -1) {
String s4 = xs.substring(0, point4);
String z4 = xs.substring(point4 + 1, xs.length());
int z4_num = z4.length();
xs = "";
double s5 = Integer.decode(s4)
+ (double) Integer.decode(z4) / (10 * z4_num);
sum = sum / s5;
} else {
sum = sum / Integer.decode(xs);
xs = "";
}
fh = 0;
break;

default:
break;
}
xs = String.valueOf(sum);
jtf.setText(xs);
fh = 0;
} else {
jtf.setText(null);
}
}

}

@Override
public void keyPressed(KeyEvent e) {
// TODO Auto-generated method stub

}

@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub

}

@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub

}

}
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