public void actionPerformed(ActionEvent e) {
    for(int i=0;i<=9;i++){
        if (flag==true){
            if (e.getSource() == btNum[i]){
                g=g+Integer.toString(i);
                jt1.setText(s.concat(g));
                c=Float.parseFloat(jt1.getText());
            }

        }
        else if(flag==false){
            if (e.getSource() == btNum[i]){
                m=m+Integer.toString(i);
                jt1.setText(s.concat(m));
                b=Float.parseFloat(jt1.getText());
            }

        }
    }

    for(int i=0;i<=3;i++){
        if (e.getSource() == btOper[i]){
            jt1.setText("");
            y=i;
            flag=false;
            g="";
            m="";
        }
    }
    if (e.getSource() == btOper[4]){
        jt1.setText("");
        flag=false;
        g="";
        m="";
    }

    if(e.getSource() == btEqual){
        switch(y){
        case 0: num=c+b;break;
        case 1: num=c-b;break;
        case 2: num=c*b;break;
        case 3: num=c/b;break;
        case 4: num=c%b;break;
        }
        jt1.setText(num+"");
        c=0;b=0;num=0;
        flag=true;
    }
}
public void click(){
    for(int i=0;i<=9;i++){
    btNum[i].addActionListener(this);
    }
    for(int i=0;i<=4;i++){
    btOper[i].addActionListener(this);
    }
    btEqual.addActionListener(this);
}
public static void main(String[]args){
    test03 c1=new test03("简易计算器");
    c1.click();
}
}