Math_Learning/src/Generator/Sen_g_ques.java

package Generator;

import java.util.Random;

public class Sen_g_ques implements G_ques{
    private Random ra= new Random();

    @Override
    public String g_question() {
        int count=ra.nextInt(5)+1;
        StringBuilder question = new StringBuilder();
        for (int i=0;i<count;i++) {
            if (i > 0) {
                question.append(" ").append(g_operator()).append(" ");
            }
            if (ra.nextDouble()<0.3){
                question.append(g_trig()).append("²").append("(").append(g_angle()).append("°)");
            }
            else {
                question.append(g_trig()).append("(").append(g_angle()).append("°)");
            }
        }
        return add_brackets(question,count);
    }

    @Override
    public String g_type(){
        return "高中";
    }

    @Override
    public char g_operator(){
        char[] op={'+','-','*','/'};
        return op[ra.nextInt(op.length)];
    }

    public String g_trig(){
        String[] trig={"sin","cos","tan"};
        return trig[ra.nextInt(trig.length)];
    }

    public String g_angle(){
        String[] angle={"15","22.5","75","105","120","135","150","210","300"};
        return angle[ra.nextInt(angle.length)];
    }

    public String add_brackets(StringBuilder s,int count){
        String res=s.toString();
        String[] parts=s.toString().split(" ");
        if (ra.nextBoolean()&&parts.length!=1) {
            int num=ra.nextInt(3)+1;
            for (int i=0;i<num;i++) {
                int pos = ra.nextInt(count);
                if (pos==count-1){
                    pos=pos-1;
                }
                parts[pos * 2] = "(" + parts[pos * 2];
                parts[parts.length-1]=parts[parts.length-1]+")";
            }
            res = String.join(" ", parts);
        }
        return res;
    }
}