import java.util.Random;

public class CreatExp {
    Random random = new Random();
    String strFile;//计算机采用的表达式
    String strPri;//打印的表达式

    public void setExpression() {
        int opNum = random.nextInt(4) + 1;//随机产生运算符数目
        int flag1 = random.nextInt(2);//随机产生分数或者整数
        CreatOpNum opnum1 = new CreatOpNum(flag1);
        opnum1.getOpNumFile();
        opnum1.getOpNumPri();
        strFile = opnum1.opnumFile;
        strPri = opnum1.opnumPri;
        pattern();
        for (int k = 2; k <= opNum; k++) {
            int flag2 = random.nextInt(2);//判断是否生成括号
            if (flag2 == 1) {//生成括号
                strFile = "(" + strFile + ")";
                strPri = "(" + strPri + ")";
                pattern();//生成一位运算符和一位运算数
            } else {
                pattern();
            }
        }

    }

    public void pattern() {//生成一个运算符加运算数的形式
        int oprChose = random.nextInt(4);//生成一个操作符
        CreateOPerator opr = new CreateOPerator(oprChose);
        strFile += opr.operator;//输出到字符串
        strPri += opr.operator;
        int flag1 = random.nextInt(2);//随机产生分数或者整数
        CreatOpNum opnum = new CreatOpNum(flag1);
        opnum.getOpNumFile();
        opnum.getOpNumPri();
        strFile += opnum.opnumFile;//输出到字符串
        strPri += opnum.opnumPri;
    }
}