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
public class Exe01 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int sum = 0; for (int i = 0; i <= 100; i++) { if ((i % 10) != 3) sum += i; } System.out.println(sum); } }
2.使用二重循环输出一下图形
*
***
*****
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public class Exe01 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub for (int i = 0; i < 5; i++) { for (int j = 0; j < -2 * i + 8; j++) { System.out.print(" "); } for (int k = 0; k < (2 * i + 1); k++) { System.out.print("* "); } System.out.println(); } } }
*****
****
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**
*
public class Exe01 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub for (int i = 0; i < 5; i++) { for (int j = 0; j < 5-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
import java.util.Scanner; public class Exe01 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner sc = new Scanner(System.in); System.out.println("请输入学生姓名"); while (true) { String name = sc.nextLine(); if ("Q".equals(name)) { System.out.println("程序结束"); break; } System.out.println("请输入学生姓名"); } } }
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 Exe01 { /** * @param args * @return */ public static void main(String[] args) { Scanner sc = new Scanner(System.in); // TODO Auto-generated method stub int sum = 0; for (int i = 0; i < 5; i++) { System.out.print("请输入第" + (i + 1) + "个学生的成绩"); int a = sc.nextInt(); if (a > 100 || a < 0) { System.out.println("输入错误,重新输入"); a = sc.nextInt(); } sum += a; } System.out.println(sum); } }
5.计算1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+......+1/(1+2+...+10)
public class Exe01 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int i = 1; double fenzi = 1; double fenmu = 0; double fenshu = fenzi / fenmu; double sum = 0; for (i = 1; i < 11; i++) { fenmu += i; fenshu = fenzi / fenmu; sum += fenshu; } System.out.println("和为" + 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”直到猜对位置
import java.util.Random; import java.util.Scanner; public class TEXT1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); Random r=new Random(); int a = r.nextInt(99); int i=1; System.out.println("输入1-99之间数"); for (i=1;i<=99;i++){ int b=input.nextInt(); if (b>i){ System.out.println("大了点"); continue; }if (b<i){ System.out.println("小了点"); continue; }else System.out.println("猜对了"); break; } } }
2.输入一个数,判断是不是质数(只要能被1和自身整除的数就是质数)
import java.util.Scanner; public class TEXT1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("请输入一个整数(大于等于2)"); int a=input.nextInt(); boolean prime=true; for (int i=2;i<a;i++){ if (a%i==0){ prime=false; break; } }if(prime){ System.out.println("是质数"); }else{ System.out.println("不是质数"); } } }
3.求斐波那契数列的第20项是什么。斐波那契数列:1,1,2,3,5,8,13,21......
public class TEXT1 { /** * @param args */ 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("斐波那契数列的第20项是:"+c); } }