Java第四次作业
- 使用for循环计算1-100的和，除了以3结尾的那些
package shangjilianxi;
public class Timu1 {
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)
continue;
sum+=i;
}
System.out.println(+sum);
}
}
package shangjilianxi;
public class Timu1 {
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)
continue;
sum+=i;
}
System.out.println(+sum);
}
}
package shangjilianxi;
public class Timu1 {
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)
continue;
sum+=i;
}
System.out.println(+sum);
}
}
package shangjilianxi;
public class Timu1 {
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)
continue;
sum+=i;
}
System.out.println(+sum);
}
}
package shangjilianxi;
public class Timu1 {
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)
continue;
sum+=i;
}
System.out.println(+sum);
}
}
2.使用二重循环输出以下图形
*
***
*****
*******
*****
****
***
**
*
package shangjilianxi;
public class Timu2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
for (int j = 1; j<=4; j++) {
for (int i = 1; i <=4-j; i++) {
System.out.print(" ");
}
for (int k=1; k<=2*j-1; k++) {
System.out.print("*");
}
System.out.println();
}
}
}
package shangjilianxi;
public class Timu2a {
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();
}
}
}
3.循环输入学生姓名，直到输入‘Q’程序结束。
package text;
import java.util.Scanner;
public class Timu3 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input=new Scanner(System.in);
System.out.println("请输入学生的姓名");
while(true) {
String name=input.next();
if("Q".equals(name)) {
System.out.println("程序结束");
break;
}
System.out.println("请输入学生的姓名");
}
}
}
4.输入5个学生成绩，求和，当输入不合法<0 >100的时候，提示输入错误重新输入。
package text;
import java.util.Scanner;
public class Timu4 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input=new Scanner(System.in);
int sum=0;
System.out.println("请输入学生的成绩");
for (int i =0 ; i <5; i++) {
double a=input.nextDouble();
if(a<0||a>100) {
System.out.println("输入错误，请重新输入");
break;
}
sum+=a;
System.out.println("请输入学生的成绩");
}
System.out.println("成绩和是"+sum);
}
}
- 计算 1+1/（1+2） + 1/（1+2+3） +1/（1+2+3+4）+…………+1/（1+2+....+10）
package diercizuoye;
import java.util.Scanner;
public class Timu8 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input=new Scanner(System.in);
double a=1;
double sum=0;
double x=0;
for (int i = 01; i <=10; i++) {
x=x+i;
sum=sum+a/x;
}
System.out.println(sum);
}
}
- 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 diercizuoye;
import java.util.Random;
import java.util.Scanner;
public class Timu6a {
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1~99的数");
Random random=new Random();
int x=random.nextInt(100);
int num=0;
while(true) {
num++;
int i=input.nextInt();
if(i>x) {
System.out.println("大了点");
}
else if(i<x){
System.out.println("小了点");
}
else {
System.out.println("答对了");
break;
}
}
if(num<=3)
System.out.println("太棒了");
else if(num>3&&num<=8) {
System.out.println("一般般");
}
else {
System.out.println("太笨了");
}
}
}
（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）
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） 12
package diercizuoye;
import java.util.Scanner;
public class Timu7a {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input=new Scanner(System.in);
int i=2,a=0;
System.out.println("请输入一个数");
int x=input.nextInt();
while(i<=x-1) {
if(x%i==0) {
a=1;
break;
}
i++;
}
if(a==0) {
System.out.println(x+"是质数");
}
else
System.out.println(x+"不是质数");
}
}
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 diercizuoye;
public class Timu8a {
public static void main(String[] args) {
// TODO Auto-generated method stub
int a=1;
int b=1;
int c=0;
for (int i = 1; i <=18; i++) {
c=a+b;
a=b;
b=c;
}
System.out.println("第二十项"+c);
}
}
