华恩JAVA班第7天

华恩JAVA班第7天

java中的循环结构,今天看书学习了三种循环结构while ， do while ， 和for ，编了三段程序

1.while：while(<条件>){<语句;>}

import java.util.*;
public class Test
{
 public static void main(String[] args)
 {
  Scanner in = newScanner(System.in);
  System.out.println("请输入该班学员总人数");
  int a = in.nextInt();
  System.out.println("该班总人数为："+a);
  int i=1;
  int sum=0;
  int average;
  while (i <=a){
   System.out.println("请输入学号"+i+"的成绩");
   int b =in.nextInt();
   System.out.println("学员"+i+"的成绩为："+b);
   i++;
   sum = sum +b;
  }
  average = sum / a;
  System.out.println("该班学员的平均成绩为："+average);
 }
}

2.do...while:do{<语句;>}while(<条件>);

import java.util.*;
public class Test
{
 public static void main(String[] args)
 {
  Scanner in = newScanner(System.in);
  int a =(int)(Math.random()*101);
  System.out.println("猜猜电脑生成的数字（0~100）"); 
  int b;
  do{
   b =in.nextInt();
   if (a> b){
    System.out.println("呜呜呜....小了，再猜");
   }else if (a< b){
    System.out.println("呜呜呜....大了，再猜");
   }else {
    System.out.println("恭喜你猜对了"); 
   }
  }
  while (a != b);
 }
}

3.for:for（表达式1；表达式2；表达式3；）{循环体}

import java.util.*;public class Test { public static void main(String[] args){  Scanner in = new Scanner(System.in);  System.out.print("请输入几门课：");  int n = in.nextInt();  System.out.print("请输入学生姓名：");  String name = in.next();  int i;  int sum = 0;  for(i = 1;i <= n;i ++){   System.out.print("请输入第"+i+"门课的成绩：");   int score = in.nextInt();   sum = sum + score;  }  System.out.println(name+"的平均分是:"+sum / n); }

}