1、判断奇数偶数
import java.util.Scanner;
public class Demo01 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("请输入一个数:");
int i = sc.nextInt();
String s = (i%2==0)?"这个数是偶数":"这个数是奇数";
System.out.println(s);
}
}

2、判断成绩是否及格
import java.util.Scanner;
public class Demo02 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入学生成绩:");
int i = scanner.nextInt();
String string = i>=60?"及格":"不及格";
System.out.println(string);
}
}

3、键盘录入并在控制台输出信息
import java.util.Scanner;
public class Demo03 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入姓名:");
String name = scanner.next();
System.out.println("请输入年龄:");
int age = scanner.nextInt();
System.out.println("请输入身高:");
int height = scanner.nextInt();
System.out.println("我的姓名是"+name+",年龄"+age+"岁,身高"+height);
}
}

4、输出一个三位数的各个位数
import java.util.Scanner;
public class Demo04 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入一个三位数:");
int num = scanner.nextInt();
int geWei=num%10;
int shiWei=num/10%10;
int baiWei=num/100%10;
System.out.println(num+"的个位是"+geWei+",十位是"+shiWei+",百位是"+baiWei);
}
}

5、计算长方形面积和周长
import java.util.Scanner;
public class Demo05 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入长方形的长:");
int length = scanner.nextInt();
System.out.println("请输入长方形的宽:");
int width = scanner.nextInt();
double area = length*width;
double girth = (length+width)*2;
System.out.println("长方形的面积为"+area+",周长为"+girth);
}
}

6、三元运算符例子
public class Demo06 {
public static void main(String[] args) {
int a = 8;
int b = 9;
int result = a>b?a+b:a*b;
System.out.println(result);
}
}

7、强制类型转换
public class Demo07 {
public static void main(String[] args) {
int i = 5;
double d = 3.14;
short s = (short)(i+d);
System.out.println(s);
}
}

8、交换两个变量的值
import java.util.Scanner;
public class Demo08 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入第一个数据:");
int a = scanner.nextInt();
System.out.println("请输入第二个数据:");
int b = scanner.nextInt();
System.out.println("交换前,a:"+a+",b:"+b);
int temp;
temp = a;
a = b;
b = temp;
System.out.println("交换后,a:"+a+",b:"+b);
}
}

9、时间路程问题
public class Demo09 {
public static void main(String[] args) {
int distanceA_B = 5;
int speedA = 1;
int speedB = 2;
int speedA_B = (speedA>speedB)?(speedA-speedB):(speedB-speedA);
int time = distanceA_B/speedA_B;
System.out.println("速度差为:"+speedA_B+",b追上a需要"+time+"秒");
}
}
