if

package test;
import java.util.Scanner;
public class bbb {
	public static void main(String[] args) {
		Scanner input=new Scanner(System.in);
		System.out.print("请输入机票价格：");
		int a=input.nextInt();
		System.out.println("请输入舱型：\n1.头等舱\n2.经济舱");
		int x=input.nextInt();
		System.out.print("请输入月份：");
		int b=input.nextInt();
		if(b>=5&&b<=10&&x==1) {
		double	c=a*0.9;
		System.out.println("打折后的机票价格为："+c);
		}else if(b>=5&&b<=10&&x==2) {
			double d=a*0.75;
			System.out.println("打折后的机票价格为："+d);
		}else if(b<5&&b>10&&x==1) {
			double e=a*0.7;
			System.out.println("打折后的机票价格为："+e);
		}else if(b<5&&b>10) {
			double f=a*0.3;
			System.out.println("打折后的机票价格为："+f);
		}
	}

}

改一下，用switch+if

package test;
import java.util.*;
public class bbb {
	public static void main(String[] args) {
		Scanner input=new Scanner(System.in);
		System.out.print("请输入月份：");
		int month=input.nextInt();
		int type; //头等舱为1，经济舱为2
		int price=4000;
		System.out.print("请输入舱位：");
		type=input.nextInt();
		switch(month) {
		case 5:
		case 6:
		case 7:
		case 8:
		case 9:
		case 10:
		    if(type==1) { 
		       System.out.println("机票价格为："+price*0.9);
		}else if(type==2) {
			   System.out.println("机票价格为："+price*0.75);
		  }
		    break;
		    default:
		    	if(type==1) {
					System.out.println("机票价格为："+price*0.7);
				}else if(type==2) {
					System.out.println("机票价格为："+price*0.3);
				}
			}
		}
	}