课后2

使用double没得出精准答案

第一个由于前面有加号，第一个是字符串，不进行计算，第二个先计算后面是字符串。
import java.util.Random;
public class MathProblemGenerator {
public static void main(String[] args) {
Random random = new Random();
for (int i = 0; i < 30; i++) {
int a = random.nextInt(100) + 1;
int b = random.nextInt(100) + 1;
int operator = random.nextInt(4);
String op;
int result;
switch (operator) {
case 0:
op = "+";
result = a + b;
break;
case 1:
op = "-";
result = a - b;
break;
case 2:
op = "*";
result = a * b;
break;
default:
op = "/";
result = a / b;
}
System.out.println(a + " " + op + " " + b + " = " + result);
}
}
}使用大概50分钟完成，需多练多思考。