练习有感：
1、String类型的数组初始化时，字符串必须用“”括起。
例题：从键盘输入1-12，显示对应月份的的单词。
import java.util.Scanner;
class Months{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
String [] months ={"January","February","March","April","May","June","July","August","September","October","November","December"};
System.out.println("Please input the month:");
int month = input.nextInt();
if(month<1||month>12){
System.out.println("the month you input is error.");
}
else{
System.out.println("the month is "+months[month-1]);
}
input.close();
}
}
2、题目类似于“将不及格的同学名字打出”，可按如下格式：
System.out.println("the students who get the best score has:");
for(int i=0;i<count;i++){
if(scores[i]==max){
System.out.println(name[i]);
}
}
3、题目要求为“随机产生偶数时”，可以运用（要求范围/2）*2的公式，则得到范围内随机偶数。
int even =(int)(Math.random()*50+1)*2;
此时，even为（150）*2=1100范围内的偶数。
例题：随机产生10个[1,100]之间的偶数，存储到数组中，并按照从小到大排序输出。
class RandomEven{
public static void main(String[] args){
int []arr=new int [10];
for(int i=0;i<arr.length;i++){
int even =(int)(Math.random()*50+1)*2;
arr[i]=even;
}
for(int i=0;i<arr.length;i++){
for(int j=0;j<arr.length-1-i;j++){
if(arr[j]>arr[j+1]){
int t=arr[j];
arr[j]=arr[j+1];
arr[j+1]=t;
}
}
}
for(int i=0;i<arr.length;i++){
System.out.println(arr[i]);
}
}
}
4.输入本组学员人数，再依次输入本组学员的成绩和姓名，最后统计：平均分、低于平均分人数、低于平均分学员姓名、最高分和最低分的姓名
可以理解姓名与成绩为一一对应的两个数组，由此遍历，得出答案。
最高分和最低分可以运用min和max在的常用思想，简单的遍历大小比较可以尝试使用三目运算符。
import java.util.Scanner;
class ExtraExerArray2{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.println("please input the count of the group:");
int count = input.nextInt();
String [] name = new String [count];
int [] scores = new int [count];
for(int i=0;i<count;i++){
System.out.println("Please input the names of the students:");
name[i]=input.next();
System.out.println("Please input the score of "+name[i]);
scores[i]=input.nextInt();}
System.out.println("The total students' scores are following:");
for(int i=0;i<count;i++){
System.out.println(name[i]+":"+scores[i]);
}
int sum=0,amount=0,average=0;
int max=scores[0],min=scores[0];
for(int i=0;i<count;i++){
sum+=scores[i];
average=sum/count;
max=scores[i]>max?scores[i]:max;
min=scores[i]<min?scores[i]:min;
}
System.out.println("The average of the scores is "+average);
System.out.println("the greatest score is "+max);
System.out.println("the lowest score is "+min);
System.out.println("the students who get the best score has:");
for(int i=0;i<count;i++){
if(scores[i]==max){
System.out.println(name[i]);
}
}
System.out.println("the students who get the lowest score has:");
for(int i=0;i<count;i++){
if(scores[i]==min){
System.out.println(name[i]);
}
}
System.out.println("the students whose score is lower the average has:");
for(int i=0;i<count;i++){
if(scores[i]<average){
System.out.println(name[i]+",");
amount++;
}
}
System.out.println("the amount of the students who didn't pass is "+amount);
input.close();
}
}
5、输入本组学员的人数，再依次输入本组学员的姓名和成绩，显示学员的姓名和成绩，最后查找是否存在满分学员。若存在，显示学员姓名，否则输出没有满分学员。
查找是否有满分学员的题目思路同上。关于查找“是否有...类型存在”，可以运用boolean类型的flag确定是否存在，此种思想常常用于确定某个判断是否存在。
import java.util.Scanner;
class FullScores{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.println("please input the count:");
int count = input.nextInt();
String []name = new String[count];
int [] scores=new int[count];
boolean flag = true;
for(int i=0;i<count;i++){
System.out.println("please input the name of the student:");
name[i]=input.next();
System.out.println("please input the scores of the student:");
scores[i]=input.nextInt();
}
for(int i=0;i<count;i++){
System.out.println("name:"+name[i]+"score:"+scores[i]);
}
for(int i=0;i<scores.length;i++){
if(scores[i]==100){
System.out.println("the student who got the full score is "+name[i]);
flag=false;
}
}
while(flag){
System.out.println("It's a pity that there is not any student gei full scores.");
}
input.close();
}
}
