简单四则运算一

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

public class Num {

	public static void main(String[] args) {
		System.out.println("练习题数：");
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		System.out.println("---------------------");
		
		int c =0;
		int result = 0;//计算结果
		int count = 0;//正确题数

		for (int j = 0; j <n; j++) {
			Random random = new Random();//运算数
			int a = random.nextInt(100);
			int b = random.nextInt(100);
			
			char[] ch = {'+','-','*','/'};
			Random ran = new Random();//运算符
			int i = ran.nextInt(ch.length);
			
			switch(i){
			case 0:
				System.out.println(a+"+"+b+"= ?");
				result=a+b;
				c++;
				break;
			case 1:
				System.out.println(a+"-"+b+"= ?");
				result=a-b;
				c++;
				break;
			case 2:
				System.out.println(a+"*"+b+"= ?");
				result=a*b;
				c++;
				break;
			case 3:
				System.out.println(a+"/"+b+"= ？");
				float x = a;
				float y = b;
				if(y!=0){
					result =(int)(x/y);    
				    }
				else{
					System.out.println("分母有误，跳过上题 ");
					break;
				}
				c++;
				break;
			}
	
		/*System.out.println("请输入答案： ");
		float an = sc.nextFloat();//输入计算结果
		
		if(an==result){
	    	  System.out.println("你真棒o(￣▽￣)ｄ -------");
	    	  count++;
	        }else{
	            System.out.println("回答错误"+"--正确结果为： "+result+"---继续努力ヾ(◍°∇°◍)ﾉﾞ------");
	        }*/
		}
	
		System.out.println("输出的题数共："+c);
		//System.out.println("共答对"+count+"道题");
	}
}