如何在这个java计算器的代码里添加计算小数的功能？？（没有C币可有偿）

public class Calculator extends JFrame implements ActionListener{
private JTextField t;
private JPanel jp;
String op="";//操作
String input;
//boolean flag=true;
private String name[]={"C","Del"," ","/","7","8","9","*","4","5","6","-","1","2","3","+"," ","0",".","="};
private JButton b[]= new JButton[name.length];

public Calculator() {
this.setTitle("计算器");
t= new JTextField(20);
this.add(t,BorderLayout.NORTH);
jp= new JPanel(new GridLayout(5,4));
for(int i=0;i<b.length;i++) {
b[i]= new JButton(name[i]);
jp.add(b[i]);
b[i].addActionListener(this);

    }
    this.add(jp,BorderLayout.CENTER);
    this.setSize(220,250);
    this.setLocation(200, 200);//设置窗体出现的位置
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //设置窗体关闭的同时关闭
    this.setVisible(true);
    this.setResizable(false);
    //validate();
}
public void actionPerformed(ActionEvent e) 
{
    int cnt=0;
    String Command=e.getActionCommand();

    if(Command.equals("+")||Command.equals("-")||Command.equals("*")||Command.equals("/")||Command.equals("."))
        input+=" "+Command+" ";//设置输入
    else if(Command.equals("C"))
        input="";
    else if(Command.equals("Del")) {
        input= input.substring(0,input.length()-1);
    }
    else if(Command.equals("="))//等号时，则处理 input
    {
        input+= "="+count(input);
        t.setText(input);
        input="";
        cnt=1;//判断是否结束一次运算
    }
    else if(Command.equals("."))
    {
        //contenTextField.append(".");
    }

    else
        input+=Command;
    if(cnt==0)
    t.setText(input);
}

private String count(String input)
{
    String str[];
    str = input.split(" ");//
    Stack<Double> s = new Stack<Double>();
    double m = Double.parseDouble(str[0]);//
    s.push(m);
    for(int i=1;i<str.length;i++)
    {
        if(i%2==1)
        {  
            if(str[i].compareTo("+")==0)  
            {  
                double help=Double.parseDouble(str[i+1]);  
                s.push(help);  
            }  

            if(str[i].compareTo("-")==0)  
            {  
                double help = Double.parseDouble(str[i+1]);  
                s.push(-help);  
            }  


            if(str[i].compareTo("*")==0)  
            {  
                double help = Double.parseDouble(str[i+1]);  
                double ans = s.peek();//取出栈顶元素  
                s.pop();//消栈  
                ans*=help;  
                s.push(ans);  
            }  

            if(str[i].compareTo("/")==0)  
            {  
                double help = Double.parseDouble(str[i+1]);  
                double ans = s.peek();  
                s.pop();  
                ans/=help;  
                s.push(ans);  
            }
        }  
    }  
    double ans = 0d;//
    while(!s.isEmpty())  
    {  
        ans+=s.peek();  
        s.pop();  
    }  
    String result = String.valueOf(ans);
    return result;
}

}

int是整数型 换成浮点型

把int类型转成double类型计算就可以正常计算了 但是会出现精度丢失的问题 如果想要精确计算的话 可以用String类型 计算时转成double计算 然后通过

DecimalFormat dFormat = new DecimalFormat("######0.00");
dFormat.format(double1 * double2)

转回字符串就可以了