import java.util.Scanner;
public class Change{
	public static void main(String[] args){
	// double cash = 100000;就是先将>50000的算出来，再将后面的算出来。
	double money;
	int count = 0;
	double restOfMoney = 100000;
	while(restOfMoney > 50000){

		money = (restOfMoney * 0.05);
		System.out.println("您需要交款：" + money + "元");
		count++;
		restOfMoney = restOfMoney - money;
		
	}

    System.out.println("还剩下" + restOfMoney + "钱");

	while(restOfMoney < 50000 && restOfMoney > 0){
		if (restOfMoney < 1000) {
			System.out.println("您的余额不足");
			System.out.println("还剩下" + restOfMoney + "钱");
			break;
		}
		restOfMoney -= 1000;
		count++;
	}

System.out.println("一共可以使用" + count + "次");
			



    }
}

老师的代码：

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		double money = 100000;
		int count = 0;//下次统计次数一定要赋值为0；
		while(true){
			// 其实这样写的话就是包括了一个范围区间。这样写才是最简单的。
			// 只是这个true不是很容易想到。
			if (money > 50000) {
			money = money * 0.95;
			count++;	
			}else if (money >=1000) {
				money -= 1000;
				count++;	
			}else{
				break;
			}
			
		}
		System.out.println("可以过这个多次" + count );

    }
}

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		Scanner myScanner = new Scanner(System.in);
		System.out.println("请输入要判断的数");
		int n1 = myScanner.nextInt();
		int n2 = n1 + n1;
		if (n2 > 0) {
			System.out.println("是正数");
		}else if (n2 == 0) {
			System.out.println("是0");		
		}else{
			System.out.println("是负数");
		}


    }
}

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		Scanner myScanner = new Scanner(System.in);
		System.out.println("请输入一个三位数");
		int num = myScanner.nextInt();
		System.out.println("三位数为： " + num);
		// 下面求百位是几。
		int bnum = num / 100;
		// 下面求十位是几。
		int snum = (num / 10) % 10;//snum = n % 100 /10
		int gnum = num % 10;
		System.out.println("百位 = " + bnum +"  " + "十位 = " + snum + "  "+ "个位 = " + gnum );

		if (bnum * bnum * bnum + snum * snum * snum + gnum * gnum * gnum == num) {
		System.out.println(num + "是水仙花数");		
		}else{
		System.out.println(num + "不是水仙花数");

		}
    }
}

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		Scanner myScanner = new Scanner(System.in);
		int num = 5;
		int count = 5;
		for (int i = 1;i <= 100 ;i++ ) {
			if ((i % 5) != 0) {
			System.out.print(i + " ");	
			count--;
			if (count == 0) {
			System.out.println(" ");	
			count = 5;	
				}
			}
		}

    }
}

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		Scanner myScanner = new Scanner(System.in);
		int num = 5;
		int count = 0;
		for (int i = 1;i <= 100 ;i++ ) {
			if ((i % 5) != 0) {
			System.out.print(i + " ");	
			count++;
			if (count % 5 == 0) {
			System.out.println(" ");	
			
				}
			}
		}

    }
}

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		Scanner myScanner = new Scanner(System.in);
		char n = 'A';
		int count = 5;
		// char tempchar;
		for (int i = 0;i <= 25 ;i++ ) {
			char tempchar = (char)(n + i);
			System.out.println("字符 = " + tempchar );
		}
			System.out.println(" ==============");

		for (int i = 0;i <= 25 ;i++ ) {
			char tempchar = (char)(n + i + 32);
			System.out.println("字符 = " + tempchar );
		}


    }
}

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		Scanner myScanner = new Scanner(System.in);
		for (char c1 = 'a';c1 <= 'z' ;c1++ ) {
			System.out.print(c1 + " ");
		}
			System.out.println(" ");

		for (char c1 = 'A';c1 <= 'Z' ;c1++ ) {
			System.out.print(c1 + " ");
		}


    }
}

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		Scanner myScanner = new Scanner(System.in);
		double value = 0 ;
		// 隐藏的一个陷阱：要把公式的分子写成1.0才能得到精确的整数才行。
		for (int i = 1;i <= 100 ;i++ ) {
			if (i % 2 != 0) {
				value =value + 1.0 / i ;
			}

			if (i % 2 == 0) {
			value =value - 1.0 / i ;
				
			}
			

		}
		System.out.println("最后的结果：  " + value);

    }
}

import java.util.Scanner;
public class Change{
	public static void main(String[] args){
		Scanner myScanner = new Scanner(System.in);
		int sum = 0;
		for (int i = 1;i <= 100 ;i++ ) {
			for (int j = 1;j <= i ;j++ ) {
				sum += j;
			}
		}
		System.out.println("最后的结果：  " + sum);

    }
}