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+"= ？");
			//除法运算结果取整
			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+"------共答对"+count+"道题");
}

}