四则运算

import java.util.Random;
import java.util.Scanner;

import javax.swing.JOptionPane;

public class yunsuan {

public static void main( String args[] ){
Random random = new Random(1);

Random rnd2 = new Random(2);
Random rnd3 = new Random(3);
int i =0;
char[] ch = new char[50];
char[] ch1= new char[50];

int[] numF = new int[50];
int[] numS = new int[50];

Scanner sc =new Scanner(System.in);
System.out.print("需要方程数");
int max= sc.nextInt();
System.out.print("是否需要乘除 1是2否");
int fglt= sc.nextInt();
switch(fglt) {
case 1 : for (i = 0; i < max; i++) {

int num = random.nextInt(4);


numF[i] = rnd2.nextInt(51);

numS[i] = rnd3.nextInt(51);
switch (num) {
case 0:
ch[i] = '+';
break;
case 1:
ch[i] = '-';
break;
case 2:
ch[i] = '*';
break;
case 3:
ch[i] = '÷';
break;

default:
break;
}

 

System.out.print( numF[i]);
System.out.print(ch[i]);
System.out.print(numS[i]);
System.out.println("=");

}break;
case 2:for (i = 0; i < max; i++) {

int num = random.nextInt(2);


numF[i] = rnd2.nextInt(51);

numS[i] = rnd3.nextInt(51);
switch (num) {
case 0:
ch[i] = '+';
break;
case 1:
ch[i] = '-';
break;
case 2:
ch[i] = '*';
break;
case 3:
ch[i] = '÷';
break;

default:
break;
}

 

System.out.print( numF[i]);
System.out.print(ch[i]);
System.out.print(numS[i]);
System.out.println("=");

}break;
}
/* for(int j=0;j<30;j++) {
for(int l=0;l<30;l++) {
if(numF[j]==numF[l]) {


}
}
}*/
/*for(int k=0;k<i;k++) {
System.out.print( numF[k]);
System.out.print(ch1[k]);
System.out.print(numS[k]);
System.out.println("=");
}*/
}
}