Java第六周作业
上机练习
1.使用for循环计算1-100的和,除了以3结尾的那些数
package exe; public class Exe1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int sum = 0; for (int i = 1; i <= 100; i++) { if (i % 10 != 3) { sum += i; } } System.out.println(sum); } }
2.使用二重循环输出以下图形
*
***
*****
*******
*****
****
***
**
*
package Class; public class Exe2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub for (int i = 1; i <= 4; i++) { for (int j = 1; j <= 4 - i; j++) { System.out.print(" "); } for (int k = 1; k <= 2 * i - 1; k++) { System.out.print("*"); } System.out.println(" "); } System.out.println(" "); for (int i = 1; i < 6; i++) { for (int j = 6 - i; j > 0; j--) { System.out.print("*"); } System.out.println(" "); } } }
3.循环输入学生姓名,直到输入‘Q’程序结束。
package Class; import java.util.Scanner; public class Exe3 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); for (int i = 1; i < i + 1; i++) { System.out.println("请输入学生姓名:"); String name = input.next(); if (name.equals("Q")) { System.out.println("结束"); break; } } } }
4.输入5个学生成绩,求和,当输入不合法的时候,提示输入错误重新输入。
package Class; import java.util.Scanner; public class Exe4 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub System.out.println("请输入五名学生成绩"); int s = 0; for (int a = 1; a <= 5; a++) { System.out.println("请输入第" + a + "名学生的成绩"); Scanner input = new Scanner(System.in); int b = input.nextInt(); if (b < 0 || b > 100) { System.out.println("输入不合法,请重新输入"); a--; } if (0 <= b && b <= 100) { s += b; } }System.out.println("和为" + s); } }
5.计算 1+1/(1+2) + 1/(1+2+3) +1/(1+2+3+4)+…………+1/(1+2+....+10)
package Class; public class Exe5 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub double sum = 0, a, b = 0; for (int i = 1; i <= 10; i++) { b += i; a = 1 / b; sum += a; } System.out.println("结果为" + sum); } }
作业
1.产生一个1-99的随机数,猜数字,若大了就提示“大了点”,若小了就提示“小了点”直到猜对为止。
(判断猜的次数,如果1-3次,提示太棒了 如果5-8次 一般般 如果8次以上 太笨了)
package Homework; import java.util.Random; import java.util.Scanner; public class Home1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int c; Random r = new Random(); int a = r.nextInt(100); System.out.println("请猜数字"); for (c = 1; c < c + 1; c++) { Scanner input = new Scanner(System.in); int b = input.nextInt(); if (b > a) System.out.println("大了点"); else if (b < a) System.out.println("小了点"); else { System.out.println("猜对了"); if (c < 3 && c > 1) System.out.println("太棒了"); else if (c > 8) System.out.println("太笨了"); else System.out.println("一般般"); break; } } } }
2.输入一个数,判断是不是质数(只能被1和自身整除的数是质数)
package Homework; import java.util.Scanner; public class Home2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int i; int c; System.out.println("请输入数字"); Scanner input = new Scanner(System.in); int a = input.nextInt(); c = 1; for (i = 2; i < 10; i++) { if (a % i == 0 && a != i) break; else c--; } if (c != 1) System.out.println("是质数"); else System.out.println("不是质数"); } }
3.求裴波那契数列的第20项是什么。裴波那契数列,1,1,2,3,5,8,13,21……
package Homework; public class Home3 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int x = 1; int y = 1; int s = 0; for (int i = 3; i < 21; i++) { s = x + y; x = y; y = s; } System.out.println("第20项为" + s); } }