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JAVA13 求平均数【循环语句】
题目:
题解:
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int num;
int sum = 0,count = 0;
while(true){
num=scan.nextInt();
if(num<0)break;
count++;
sum+=num;
}
//没有下面这行代码的一律不及格
scan.close();
if(count>0){
double avg=(double)sum/count;
System.out.println(String.format("%.2f",avg));
}
}
}
JAVA14 判断质数【循环语句】
题目:
题解:
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Main main = new Main();
Scanner scan = new Scanner(System.in);
int number = scan.nextInt();
System.out.println(main.isPrimeNumber(number));
}
public Boolean isPrimeNumber(int number) {
if (number == 2) return true;//判断质数从2开始
int i = 3 ; //若不是2 , 依次判断3,5,7,9···
if (number != 2 && number % 2 == 0) return false;//质数是不等于2的奇数
for (; number % i != 0; i += 2); //当能整除某个奇数时退出循环
return i == number ? true :false; //判断是否是因为整除自己才退出循环
}
}
JAVA15 计算整数位数【运算符】
题目:
题解:
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
double d= scanner.nextDouble();
scanner.close();
//好家伙,这也太强了,简单粗暴
int i = (int)(d+0.5);
System.out.println(i);
}
}