JAVA随机生成四则运算

import java.sql.SQLOutput;
import java.util.Random;
import java.util.Scanner;

public class newNum {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int num1;
        System.out.println("请输入操作数的个数：1(2个)， 2（3个）");
        num1 = sc.nextInt();

        switch (num1) {

            case 1:
                case1();
                break;
            case 2:
                case2();
                break;


        }


    }

    public static void myInsert(StringBuffer str, int num) {

        Random rand = new Random();
        while(true) {
            int i = rand.nextInt((num - 1) * 3 - 2);
            if (i % 3 == 0) {

                str.insert(i, "(");
                str.insert(i + 6, ")");
                break;

            }
        }

    }

    public static void case1() {
        Scanner sc = new Scanner(System.in);
        int num2;
        System.out.println("是否加入乘除：1（是）， 2（否）");
        num2 = sc.nextInt();
        System.out.println("请输入你要打印的题数：");
        int m = sc.nextInt();
        Random rand = new Random();
        int i, j, k;
        String[] s = new String[m];
        for(int o = 0; o < m; o++) {
            i = rand.nextInt(4);
            j = rand.nextInt(100);
            k = rand.nextInt(100);
            char Fuhao;
            if(i == 0) {

                Fuhao = '+';

            }else if (i == 1) {
                Fuhao = '-';

            }else if (i == 2) {

                Fuhao = '*';

            }else if (i == 3) {

                Fuhao = '/';
            }
            StringBuffer str = new StringBuffer();
            s[o] = str.append(i).append(j).append(k).toString();


            int sum = 0;
            for(int q = 0; q < s.length; q++) {

                if(s[o].equals(s[q])) {
                    sum++;
                }

            }

            if(sum == 1) {

                if(i == 0) {

                    System.out.println(j + "+" + k + "=");
                }
                if(i == 1) {

                    System.out.println(j + "-" + k + "=");
                }
                if(i == 2) {

                    if(num2 == 1) {
                        System.out.println(j + "*" + k + "=");

                    }else {

                        o--;
                        continue;
                    }
                    }
                if(i == 3) {
                    if(num2 == 1) {
                        if (k == 0) {

                            o--;
                            continue;

                        } else {
                            System.out.println(j + "/" + k + "=");
                        }
                    }else {

                        o--;
                        continue;

                    }
                }

            }else if(sum != 1){
                o--;
                continue;

            }

        }

    }

    public static void case2() {

        Scanner sc = new Scanner(System.in);
        int num2, num3, num4;
        System.out.println("请输入操作数的范围：");
        num4 = sc.nextInt();
        System.out.println("是否加入乘除：1（是）， 2（否）");
        num2 = sc.nextInt();
        System.out.println("是否加入括号：1（是）， 2（否）");
        num3 = sc.nextInt();
        System.out.println("请输入你要打印的题数：");
        int m = sc.nextInt();
        Random rand = new Random();
        int i, j, k, l,u;
        String[] s = new String[m];
        for(int o = 0; o < m; o++) {
            if(num2 == 2) {
                i = rand.nextInt(2);
                u = rand.nextInt(2);
            }else {
                i = rand.nextInt(4);
                u = rand.nextInt(4);
            }
            l = rand.nextInt(num4);
            j = rand.nextInt(num4);
            k = rand.nextInt(num4);
            String Fuhao = "", Fuhao2 = "";
            if(i == 0) {

                Fuhao = "+";

            }else if (i == 1) {
                Fuhao = "-";

            }else if (i == 2) {

                Fuhao = "*";

            }else if (i == 3) {

                Fuhao = "/";
            }
            if(u == 0) {

                Fuhao2 = "+";

            }else if (u == 1) {
                Fuhao2 = "-";

            }else if (u == 2) {

                Fuhao2 = "*";

            }else if (u == 3) {

                Fuhao2 = "/";
            }
            StringBuffer str = new StringBuffer();
            StringBuffer str1 = new StringBuffer();
            s[o] = str.append(i).append(j).append(k).toString();

            str1.append(l).append(Fuhao).append(j).append(Fuhao2).append(k).append("=");

            int sum = 0;
            for(int q = 0; q < s.length; q++) {

                if(s[o].equals(s[q])) {
                    sum++;
                }

            }




            if(sum == 1) {


                if(num3 == 1) {

                    /*myInsert(str1, 3);
                    String str4 = str1.toString();
                    System.out.println(str4);
                     */
                    int i3 = rand.nextInt(2);

                            if(i3 == 0) {

                                System.out.println("(" +l + Fuhao + j + ")" + Fuhao2 + k + "=");

                            }
                            if(i3 == 1) {

                                System.out.println(l + Fuhao + "(" +j + Fuhao2 + k + ")");

                            }
                            

                }else {

                    System.out.println(l + Fuhao + j + Fuhao2 + k + "=");

                }


            }else if(sum != 1){
                o--;
                continue;

            }

        }

    }

}