1.奇偶数
package DY1;
public class Jioushu {
public static void main(String[] args) {
int a=5;
if(a%2==0)
{
System.out.println("偶数");
}
else
{
System.out.println("奇数");
}
}
}
2.圆面积
package DY1;
import java.util.*;
public class Syuan {
public static void main(String[] args) {
Scanner in =new Scanner(System.in);
int r=in.nextInt();
double s;
final double Pai=3.14;
s=Pai*r*r;
System.out.println(s);
}
}
3.加密
package DY1;
import java.util.*;
public class Jiami {
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
int a=in.nextInt();
double b;
b=(a*10+5)/2+3.14159;
int i=(int)b;
System.out.println(i);
}
}
4.公鸡
package DY1;
public class Gongji {
public static void main(String[] args) {
int gong,mu,xiao,count=0;
for(gong=0;gong<20;gong++)
{
for(mu=0;mu<33;mu++)
{
for(xiao=0;xiao<100;xiao++)
{
if(xiao%3==0)
{
if((gong+mu+xiao==100)&&gong*5+mu*3+xiao/3==100)
count ++;
System.out.println("公鸡："+gong+"只，母鸡"+mu+"只,小鸡"+xiao+"只");
}
}
}
}
System.out.println("一共"+count+"种买法");
}
}
5.数字组合
package DY1;
public class shuzi {
public static void main(String[] args) {
int i,j,k,s=0;
for(i=1;i<=4;i++)
{
for(j=1;j<=4;j++)
{
for(k=1;k<=4;k++)
{
if(i!=j&&j!=k&&k!=i)
{
s=s+1;
System.out.println(i*100+j*10+k);
}
}
}
}
}
}
6.素数
package DY1;
import java.util.*;
public class Sushu {
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
int a=in.nextInt();
if(a<2) {
System.out.println("不是素数");
}
for(int i=1;i<a;i++)
{
if(a%i==0)
{
if(a==i)
System.out.println("是素数");
}
else if(i!=1)
{
System.out.println("不是素数");
break;
}
}
}
}