将一个数组逆序输出
import java.util.Arrays;
public class ShuZuNiXu {
public static void main(String[] args) {
// TODO Auto-generated method stub
int a[]={11,12,34,45,63,21,66,88,9};
int b[]=new int[a.length];
for(int i=0;i<a.length;i++) {//新数组
b[i]=a[a.length-1-i];
System.out.print(b[i]+" ");
}
System.out.println();
System.out.println("数组逆序输出为:"+Arrays.toString(b));
}
}
取一个整数a从右端开始的4~7位
import java.util.Scanner;
public class SiQiWei {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner get =new Scanner(System.in);
long num=get.nextLong();
int a=(int)(num%(Math.pow(10, 7))-num%(Math.pow(10, 3)))/1000;
System.err.println(a);
get.close();
}
}
打印出杨辉三角形
import java.util.Scanner;
public class YangHuiSanJiao {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner get=new Scanner(System.in);
int n=get.nextInt();
int m[][]=new int[n+1][n+1];
m[0][0]=1;
m[1][0]=m[1][1]=1;
if(n==1) {
System.out.println(m[0][0]);
}
if(n==2) {
System.out.println(m[0][0]);
System.out.println(m[1][0]+" "+m[1][1]);
}
if(n>2) {
System.out.println(m[0][0]);
System.out.println(m[1][0]+" "+m[1][1]);
for(int i=2;i<n;i++) {
m[i][0]=m[i][i]=1;
System.out.print(m[i][0]+" ");
for(int j=1;j<i;j++) {
m[i][j]=m[i-1][j-1]+m[i-1][j];
System.out.print(m[i][j]+" ");
}
System.out.println(m[i][i]);
}
}
get.close();
}
}
输入3个数a,b,c,按大小顺序输出
import java.util.Scanner;
public class ABCpaiXu {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner get=new Scanner(System.in);
int a=get.nextInt();
int b=get.nextInt();
int c=get.nextInt();
int temp;
if(a<b) {
temp=b;
b=a;
a=temp;
}
if(c>a) {
System.out.println(c+">"+a+">"+b);
}
else if(c>b) {
System.out.println(a+">"+c+">"+b);
}
else {
System.out.println(a+">"+b+">"+c);
}
}
}
输入数组,最大的与第一个元素交换,最小的与最后一个元素交换,输出数组
import java.util.Scanner;
public class ShuZu {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner get =new Scanner(System.in);
int array[]=new int[10];
for(int i=0;i<10;i++) {
array[i]=get.nextInt();
}
for(int i=0;i<10;i++) {
if(array[i]>array[0])
array[0]=array[i];
if(array[i]<array[array.length-1])
array[array.length-1]=array[i];
}
for(int j=0;j<array.length;j++) {
System.out.print(array[j]+" ");
}
get.close();
}
}
有n个整数,使其前面各数顺序向后移m个位置,最后m个数变成最前面的m个数
import java.util.Scanner;
public class HouYi {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner get=new Scanner(System.in);
System.out.println("请输入n个数:");
int n=get.nextInt();
System.out.println("输入一个数m,使n个数向后移m位:");
int m=get.nextInt();
int arr[]=new int[n];
int arr1[]=new int[n];
for(int i=0;i<n;i++) {
arr[i]=get.nextInt();
}
for(int i=0;i<n;i++) {
for(int j=m;j<n;j++) {
arr1[j]=arr[j-m];
}
for(int k=0;k<m;k++) {
arr1[k]=arr[n-m+k];
}
System.out.println(arr1[i]+" ");
}
}
}
有n个人围成一圈,顺序排号。从第一个人开始报数(从1到3报数),凡报到3的人退出圈子,问最后留下的是原来第几号的那位
import java.awt.Toolkit;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Toolkit t=Toolkit.getDefaultToolkit();
t.beep();
System.out.println("请输入总人数:");
Scanner get=new Scanner(System.in);
int n=get.nextInt();
get.close();
boolean isin[]=new boolean[n];
for(int i=0;i<isin.length;i++) {
isin[i]=true;
}
int count=n;//圈内剩余总人数
int num=0;//定义报数
int index=0;//索引
while(count>1) {//循环直至最后一个人count=1
if(isin[index]) {//此处限制index要小于n
num++;
if(num==3) {
isin[index]=false;
num=0;
count--;
}
}
index++;
if(index==n) {
index=0;
}
}
for(int i=0;i<n;i++) {
if(isin[i]) {
System.out.println("留下的是:"+(i+1));
}
}
}
}
写一个函数,求一个字符串的长度,在main函数中输入字符串,并输出其长度
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner get=new Scanner(System.in);
String s=get.nextLine();
Alength(s);
get.close();
}
static void Alength(String s) {
System.out.println("字符串的长度为:"+s.length());
}
}
编写一个函数,输入n为偶数时,调用函数求1/2+1/4+…+1/n,当输入n为奇数时,调用函数1/1+1/3+…+1/n(利用指针函数)
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Main m=new Main();
Scanner get=new Scanner(System.in);
int n=get.nextInt();
if(n%2==0) {
double d=even(n);
System.out.println("偶数的和为:"+d);
}
else {m.odd(n);}
get.close();
}
static double even(int n) {
double sum=0.0;
for(double i=2;i<=n;) {
sum+=(1/i);
i=i+2;
}
return sum;
}
public void odd(int n) {
System.out.println("奇数的和为:");
float sum=0;
for(float i=1;i<=n;) {
sum+=(float)(1/i);
if(i<n) {
System.out.print("1/"+(int)i+"+");
}else {
System.out.print("1/"+(int)i);
}
i=i+2;
}
System.out.println("="+sum);
}
}
字符串排序
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
String s[]= {"hello","alter","tell","number"};
for(int i=1;i<s.length;i++) {
if(s[i].compareTo(s[i-1])<0) {
String s0=s[i];
s[i]=s[i-1];
s[i-1]=s0;
}
}
for(String ss:s) {
System.out.print(ss+" ");
}
}
}