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 sdsd; import java.util.Scanner; public class Test1111 { 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 sdsd; import java.util.Scanner; public class Test1111 { 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 m = 1; m <= i * 2 - 1; m++) { System.out.print("*"); } System.out.println("\n"); } System.out.println("\n"); } }
*****
****
***
**
*
package sdsd; import java.util.Scanner; public class Test1111 { public static void main(String[] args) { // TODO Auto-generated method stub for (int i = 1; i <= 5; i++) { for (int j = 1; j <= 6 - i; j++) { System.out.print("*"); } System.out.println("\n"); } System.out.println("\n"); } }
3.循环输入学生姓名,直到输入‘Q’程序结束。
package sdsd;
import java.util.Scanner;
public class Test1111 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("输入学生姓名");
Scanner input = new Scanner(System.in);
String name = input.next();
while (name != "Q") {
name = input.next();
if (name.equals("Q"))
System.out.println("程序结束");
}
}
}
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 sdsd; import java.util.Scanner; public class Test1111 { public static void main(String[] args) { // TODO Auto-generated method stub int sum=0; Scanner input=new Scanner(System.in); System.out.println("输入学生成绩"); for(int i=1;i<=5;i++){ int grade=input.nextInt(); while(grade<0||grade>100){ System.out.println("输入错误重新输入"); grade=input.nextInt(); } 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 sdsd; import java.util.Scanner; public class Test1111 { public static void main(String[] args) { // TODO Auto-generated method stub double a = 1; double b = 0; double sum = 0; for (int i = 1; i <= 10; i++) { b = b + i; sum = sum + a / b; } System.out.println(sum); } }
6.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。
package sdsd; import java.util.Random; import java.util.Scanner; public class Test1111 { 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; } } } }
7.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 sdsd; import java.util.Scanner; public class Test1111 { 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; } } } }
8.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 sdsd; import java.util.Scanner; public class Test1111 { 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); } }