JAVA编写简易计算器

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本文介绍了一个简易计算器的设计过程，包括使用Java Swing实现基本功能，并通过引入C语言算法改进运算顺序处理，实现了更高级的功能。

最近老是布置了JAVA课后作业，自己编写一个简易计算器，本渣渣利用为数不多的JAVA知识，写下了这个真的极其简易的计算器。。。

先展示一下运行效果

可惜这个计算器如果要计算，只能按照先后顺序进行运算，不能自动分辨+-*/的运算顺序，下面上代码

package p1;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
@SuppressWarnings("serial")
public class JSQdeg extends JFrame {
	int sum = 0;
	int f=0;
	String t2;
	String l="";
	char ch = ' ';//当前字符
	int k=0;
	JButton jbt[][] = new JButton[4][4];
	JTextField t1 = new JTextField(20);
	public JSQdeg() {
		t1.setEditable(false);
		GridLayout gridLayout = new GridLayout(4,0); // 创建网格布局管理器对象
       gridLayout.setHgap(5); // 设置组件的水平间距
        gridLayout.setVgap(5); // 设置组件的垂直间距
        JPanel panel = new JPanel(); // 获得容器对象
        panel.setLayout(gridLayout); // 设置容器采用网格布局管理器
        this.add(panel, BorderLayout.CENTER);
		String name[][] = {{"1","2","3","+"},{"4","5","6","-"},{"7","8","9","*"},{"AC","0","=","/"}};
		for(int i = 0;i<4;i++) {
			for(int j = 0;j<4;j++) {
				jbt[i][j] = new JButton(name[i][j]);
				jbt[i][j].addActionListener(new ActionLis());
				panel.add(jbt[i][j]);
			}
		}
		this.add(BorderLayout.CENTER,panel);
		this.add(BorderLayout.NORTH,t1);
		this.setVisible(true);
		this.setSize(350, 200);
	}
	class ActionLis implements ActionListener{
		public void actionPerformed(ActionEvent e) {
			JButton b = (JButton) e.getSource();
			t2 = b.getText();
			if(t2 == "AC") {
				t1.setText(" ");
				l = "";
				ch = ' ';
				sum = 0;
				k = 0;
			}else {
				switch(t2){
				case "+":
				case "-":
				case "*":
				case "/": changech(t2);break;
				case "=": jieguo(t2);break;
				default : getsum(); break;
				}
			}
		}
		private void getsum() {
			if(ch == ' ') {
				l += t2;
				t1.setText(l);
				sum = Integer.parseInt(l);
			}else {
				l += t2;
				t1.setText(l);
				k = Integer.parseInt(l);
			}
		}
	}
		private void jieguo(String t2) {
			switch(ch){
			case '+':sum += k;break;
			case '-':sum -= k;break;
			case '*':sum *= k;break;
			case '/':sum /= k;break;
			}
			l = String.valueOf(sum);
			t1.setText(l);
			l = "";
			ch = ' ';
			sum = 0;
			k = 0;
			f = 0;
		}
	public static void main(String[] args) {
		new JSQdeg();
	}
	public void changech(String t22) {
		switch(ch){
		case '+':sum += k;break;
		case '-':sum -= k;break;
		case '*':sum *= k;break;
		case '/':sum /= k;break;
		}
		ch = t22.charAt(0);
		l = String.valueOf(sum);
		t1.setText(l);
		l = "";
	}
}

这个计算器由于并不能自动分辨计算顺序，所以在计算上还是有点LOW的，后来想起来，曾经用C语言写过一次计算器，而且是可以计算先后顺序的，便把这段C语言稍加更改之后，放入了程序中，瞬间，计算器就变得很完美了

附上代码

package p1;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
@SuppressWarnings("serial")
public class JSQdeg extends JFrame {
	JButton jbt[][] = new JButton[4][4];
	JTextField t1 = new JTextField(20);
	JButton ac = new JButton("AC");
	String s2 = "";
	String textname;
	public JSQdeg() {
		t1.setEditable(false);
		GridLayout gridLayout = new GridLayout(4,0); // 创建网格布局管理器对象
        gridLayout.setHgap(5); // 设置组件的水平间距
        gridLayout.setVgap(5); // 设置组件的垂直间距
        JPanel panel = new JPanel(); // 获得容器对象
        panel.setLayout(gridLayout); // 设置容器采用网格布局管理器
        this.add(panel, BorderLayout.CENTER);
		String name[][] = {{"1","2","3","+"},{"4","5","6","-"},{"7","8","9","*"},{"CE","0","=","/"}};//预先设定按钮名称
		for(int i = 0;i<4;i++) {
			for(int j = 0;j<4;j++) {
				jbt[i][j] = new JButton(name[i][j]);//将按钮名称添加到按钮上
				jbt[i][j].addActionListener(new ActionLis());//给按钮添加监听器
				jbt[i][j].setBackground(Color.cyan);//设置按钮背景颜色
				jbt[i][j].setForeground(Color.DARK_GRAY);//设置按钮字体颜色
				jbt[i][j].setFont(new Font("宋体", Font.PLAIN, 16));//设置按钮字体样式大小
				panel.add(jbt[i][j]);//将按钮添加到面板上
			}
		}
		ac.addActionListener(new ActionLis());
		ac.setBackground(Color.cyan);//设置按钮背景颜色
		ac.setForeground(Color.red);//设置按钮字体颜色
		ac.setFont(new Font("宋体", Font.PLAIN, 16));//设置按钮字体样式大小
		this.add(BorderLayout.CENTER,panel);
		this.add(BorderLayout.NORTH,t1);
		this.add(BorderLayout.SOUTH,ac);
		this.setVisible(true);
		this.setSize(350, 200);
	}
	class ActionLis implements ActionListener{
		@SuppressWarnings("null")
		public void actionPerformed(ActionEvent e) {
			JButton b = (JButton) e.getSource();
			String btname = b.getText();
			if(btname == "="){
				double a[] = new double[1000];
				int i,k,s,f = 0;
				k=0;
		        int l = s2.length();
		        s2 += "@";
		        for(i=0; i<l;) {
		            if(s2.charAt(i)>='0'&&s2.charAt(i)<='9') {
		                s=0;
		                while(s2.charAt(i)>='0'&&s2.charAt(i)<='9') {
		                    s*=10;
		                    s+=s2.charAt(i)-'0';
		                    i++;
		                }
		                a[k]=s;
		                k++;
		            }
		            switch(s2.charAt(i)) {
		            case '+': a[k] = -1;k++;i++;break;
		            case '-': a[k] = -2;k++;i++;break;
		            case '*': a[k] = -3;k++;i++;break;
		            case '/': a[k] = -4;k++;i++;break;
		            }
		        }
		        for(i=0; i<k; i++) {
		            if(a[i]==-3||a[i]==-4) {
		                if(a[i]==-3) {
		                    a[i+1]=(a[i-1]*a[i+1]*1.0);
		                    a[i-1]=-5;
		                    a[i]=-5;
		                }
		                if(a[i]==-4) {
		                    a[i+1]=a[i-1]/a[i+1]*1.0;
		                    a[i-1]=-5;
		                    a[i]=-5;
		                }
		            }
		        }
		        double s1 = 0;
		        for(i=0;i<k;i++) {
		            if(a[i]!=-5) {
		                s1=a[i];
		                break;
		            }
		        }
		        for(i=1; i<k;) {
		            if(a[i]==-1||a[i]==-2) {
		                if(a[i]==-1)
		                    f=1;
		                else
		                    f=2;
		                i++;
		            }
		            if(f==1&&a[i]!=-5)
		                s1+=a[i];
		            if(f==2&&a[i]!=-5)
		                s1-=a[i];
		            i++;
		        }
		        textname = Double.toString(s1);
		        t1.setText(textname);
		        s2 = "";
			}else if(btname == "CE") {
				int l = s2.length();
				s2 = s2.substring(0,l-1);
		        t1.setText(s2);
			}else if(btname == "AC") {
				s2 = " ";
		        t1.setText(s2);
			}
			else{
				s2 += btname;
				t1.setText(s2);
			}
		}
	}
	public static void main(String[] args) {
		new JSQdeg();
		}
}