java第六次作业
1.使用for循环计算1-100的和,除了以3结尾的那些数
package work; public class work { public static void main(String[] args) { int sum=0; for (int i = 1; i < 101; 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 work; public class work { public static void main(String[] args) { int sum=0; for (int i = 1; i <= 4; i++) { for (int j = 1; j <= i*2-1; j++) { System.out.print("*"); } System.out.println( ); } } }
package work; public class work { public static void main(String[] args) { int sum=0; for (int i = 0; i <= 5; i++) { for (int j = 1; j <= 6-i; 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 work; import java.util.Scanner; public class work { public static void main(String[] args) { Scanner input=new Scanner(System.in); for (int i = 1; i < 100; i++) { String name=input.next(); System.out.println(); if (name.equals("Q")) { System.out.println("程序結束"); 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 work; import java.util.Scanner; public class work { public static void main(String[] args) { Scanner input=new Scanner(System.in); System.out.println("输入五名学生成绩"); int sum=0; for (int i = 0; i < 5; i++) { int grade = input.nextInt(); while (grade<0 || grade>100) { System.out.println("输入无效,重新输入"); grade = input.nextInt(); break; } sum+=grade; } System.out.println(sum); } }
5.计算 1+1/(1+2) + 1/(1+2+3) +1/(1+2+3+4)+…………+1/(1+2+....+10)
package work; public class work { public static void main(String[] args) { double sum=0; double a=0; for (int i = 1; i < 11; i++) { a+=i; sum+=1/a; } System.out.println(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 work; import java.util.Random; import java.util.Scanner; public class work { public static void main(String[] args) { Scanner input=new Scanner(System.in); System.out.println("猜数字"); int s=input.nextInt(); Random r = new Random(); int a = r.nextInt(99) + 1; while (a!=s) { if (s>a) { System.out.println("大了点"); } if (s<a) { System.out.println("小了点"); } System.out.print("再猜"); s = input.nextInt(); } System.out.println("猜对了"); } }
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 work; import java.util.Random; import java.util.Scanner; public class work { public static void main(String[] args) { Scanner input=new Scanner(System.in); System.out.println("输入大于1的数"); boolean n = true; int a=input.nextInt(); for (int i = 2; i < a-1; i++) { if (a%i==0) { n = false; break; } } if (n) { 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 work; public class work { public static void main(String[] args) { int a=1,b=1,c=0; for (int i = 1; i < 19; i++) { c=a+b; a=b; b=c; } System.out.println("第二十项是:"+c); } }