软件构造-口算题卡

实现重复题目的检测功能

package ruanjiangouzao;
import java.util.Random;
public class secondhomework {
        static String [] e = new String[50];
        static short [] r = new short[50];
        public static void printHeader(){
            System.out.println("--------------------------------------");
            System.out.println("- 程序输出50道100以内的加法减法算式的习题 -");
            System.out.println("- 每次运行程序可得到一套50道题的习题及答案 -");
            System.out.println("--------------------------------------");
        }
        public static void generateEquations(){
            short m=0, n=0,v=0,ov = 0;          
            char o='+';
            Random random = new Random();
            for (int i=0;i<50; i++){
                ov = (short) random.nextInt(2); 
                m = (short)random.nextInt(101);        // 随机产生运算数
                if (ov == 1){
                    do {
                        n = (short)random.nextInt(101);
                        v = (short) (m + n);
                    } while (100 < v || v < 0);            
                    o = '+';
                } else {
                    do {
                        n = (short)random.nextInt(101);
                        v = (short) (m - n);
                    } while (100 < v || v < 0);
                    o = '-';
                }            
                e[i]=""+m+o+n+"=";
                r[i]=v;
                if(chachong(e,i)==0){             //检查重复的题目
                    i--;
                }else if(r[i]>100||r[i]==100){    //口算结果小于100
                    i--;
                }
            }
        }
        public static int chachong(String [] e,int i){  //查重函数
            for(int j=0;j<i;j++) {
                 if(e[i].equals(e[j])) {
                     return 0;                 
                 }
            }
            return 1;
        }
        public static void printExercise(){
            for (int i=0;i<e.length; i++){
                System.out.println(""+(i+1)+":\t"+e[i]);
            }
        }
        public static void printCalculations(){
            for (int i=0;i<r.length; i++){
                System.out.println(""+(i+1)+":\t"+r[i]);
            }
        }
        public static void main(String[] args) {
            printHeader();
            generateEquations();
            printExercise();
            System.out.println();
            System.out.println("---------------------------");
            System.out.println("- 下面是习题的参考答案    ");
            printCalculations();    
        }
}