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 Zf1 { public static void main(String[] args) { // TODO Auto-generated method stub int i; int sum=0; for(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 work; public class Zf2 { public static void main(String[] args) { // TODO Auto-generated method stub int a,b,c; for(a=1;a<=4;a++) { for(b=1;b<=4-a;b++) { System.out.print(" "); } for(c=1;c<=2*a-1;c++) { System.out.print("*"); } System.out.print("\n"); } } }
package work; public class Zf3 { public static void main(String[] args) { // TODO Auto-generated method stub int i,j; for(i=1;i<=5;i++) { for(j=5;j>=i;j--) { System.out.print("*"); } System.out.print("\n"); } } }
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 Zf4 { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); while(true) { System.out.println("输入学生姓名"); String name=input.next(); if(name.equals("Q")) { System.out.println("程序结束"); break; } System.out.println("重新"); } } }
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。
import java.util.Scanner; public class homework3 { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); double sum = 0; System.out.println("请输入5个学生的成绩:"); for (int i = 1; i <= 5; i++) { System.out.println("请输入第" + i + "个学生的成绩:"); double a = input.nextDouble(); if (a > 100 || a < 0) { System.out.println("提示:输入错误重新输入!"); break; } sum += a; } System.out.println("输入5个学生的成绩和为" + sum); } }
5.计算 1+1/(1+2) + 1/(1+2+3) +1/(1+2+3+4)+…………+1/(1+2+....+10)
public class homework3 { public static void main(String[] args) { // TODO Auto-generated method stub double a = 1;// 分字 double b = 0;// 分母 double sum = 0; for (int i = 1; i <= 10; i++) { b = b + i; sum = sum + a / b; } 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。
import java.util.Random; import java.util.Scanner; public class homework3 { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); Random a = new Random(); int b = a.nextInt(99); int i = 1; System.out.println("请猜一个数字(1~99):"); for (i = 1; i <= 99; i++) { int num = input.nextInt(); if (num > b) { System.out.println("大了点"); continue; } if (num < b) { System.out.println("小了点"); continue; } if (num == b) { System.out.println("猜对了"); 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)
import java.util.Scanner; public class homework3 { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); System.out.println("请输入一个数(该数大于1):"); int num = input.nextInt(); for (int i = 2; i <= num; i++) { if (num % i == 0 && num != i) { System.out.println(num + "不为质数,能被" + i + "整除"); break; } else { System.out.println(num + "为质数!"); break; } } } }
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……
public class homework3 { public static void main(String[] args) { // TODO Auto-generated method stub int a = 1, b = 1, c = 0; for (int i = 1; i <= 18; i++) { c = a + b; a = b; b = c; } System.out.println("裴波那契数列的第20项是:" + c); } }