第六周上机+练习4.10
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 week6; public class S1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int sum=0; for (int a=1;a<=100;a++) { if(a%10!=3&&a!=3) { sum+=a; } } System.out.println(sum); } }
2.使用二重循环输出以下图形
*
***
*****
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package week6; public class S22 { /** * @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<=5-i; j++) { System.out.print(" "); } for (int j2 = 1; j2<=2*i-1; j2++) { System.out.print("*"); } System.out.println(" "); } } }
*****
****
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**
*
package week6; public class S2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub for (int a=1;a<=5;a++) { for (int b=1;b<=6-a;b++) { 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 week6; import java.util.Scanner; public class S3 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); String name=input.next(); int time=0; while(time>=0) { if(name.equals("Q")) { System.out.println("ok"); break; } else { System.out.println("重新输入"); String rename=input.next(); name=rename; } } } }
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 week6; import java.util.Scanner; public class S4 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); int g1=input.nextInt(); int g2=input.nextInt(); int g3=input.nextInt(); int g4=input.nextInt(); int g5=input.nextInt(); while(g1<=0||g1>=100||g2<=0||g2>=100||g3<=0||g3>=100||g4<=0||g4>=100||g5<=0||g5>=100) { System.out.println("不合法,重新输入"); int g6=input.nextInt(); int g7=input.nextInt(); int g8=input.nextInt(); int g9=input.nextInt(); int g10=input.nextInt(); g1=g6; g2=g7; g3=g8; g4=g9; g5=g10; } if(g1>=0&&g1<=100&&g2>=0&&g2<=100&&g3>=0&&g3<=100&&g4>=0&&g4<=100&&g5>=0&&g5<=100) { System.out.println("ok"); } } }
5.计算 1+1/(1+2) + 1/(1+2+3) +1/(1+2+3+4)+…………+1/(1+2+....+10)
package week6; public class S5 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub double sum=0; double num=0; for(int i=1;i<=10;i++) { sum=sum+i; num=num+1/sum; } System.out.println(num); } }
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 week6; import java.util.Random; import java.util.Scanner; public class W1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Random r=new Random(); int x=r.nextInt(99); Scanner input=new Scanner(System.in); int a=input.nextInt(); int y=1; while(y>=1){ if (a>x) { System.out.println("大了点"); int b=input.nextInt(); a=b; y++; } else if (a<x) { System.out.println("小了点"); int b=input.nextInt(); a=b; y++; } else{ System.out.println("ok"); if(y<=3&&y>=1){ System.out.println("太棒了"); break;} else if (y>=4&&y<=8){ System.out.println("一般般"); break;} else { System.out.println("太笨了"); 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)
package week6; import java.util.Scanner; public class W2 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); int a=input.nextInt(); if(a%2==0||a/10>0&&a%3==0||a%4==0||a/10>0&&a%5==0||a%6==0||a/10>0&&a%7==0||a%8==0||a%9==0) { System.out.println("不是质数"); } else { System.out.println("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 week6; public class W3 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a=1; int b=1; int c=0; for(int time=1;time<=18;time++) { c=a+b; a=b; b=c; } System.out.println(b); } }