---
# System prepended metadata

title: 17號筆記
tags: [筆記本]

---

# 17號筆記
###### tags: `筆記本`
# 1.Switch 月份用法

```
 public class SwitchDemo {

	public static void SumMonthDaysBySwitch(int month) {
		switch (month) {
		case 1:
		case 3:
		case 5:
		case 7:
		case 8:
		case 10:
		case 12:
			System.out.println("31 days");
			break;
		case 2:
			System.out.println("28 days");
			break;
		case 4:
		case 6:
		case 9:
		case 11:
			System.out.println("30 days");
			break;
		default:
			System.out.println("Invalid month");//無效月份
			break;
			
}
		
}
	public static void SumMonthDaysByIf(int month) {
		if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) {
			System.out.println("31 days");
		}else if (month == 2) {
			System.out.println("28 days");
		}else if (month == 4 || month == 6 || month == 9 || month == 11 ) {
			System.out.println("30 days"); 
		}else {
			System.out.println("Invalid month");
}
}
	public static void main(String[] args) {
		SumMonthDaysByIf(2);
		SumMonthDaysBySwitch(2);
		
}
	
	
}
```
```
public class SwitchDemo2 {

	public static void SumMonthDaysBySwitch2(int month) {
		switch (month) {
		case 1:
			System.out.println("--1");
		case 3:
			System.out.println("--3");
		case 5:
			System.out.println("--5");
		case 7:
			System.out.println("--7");
		case 8:
			System.out.println("--8");
		case 10:
			System.out.println("--10");
		case 12:
			System.out.println("31 days");
			break;
		case 2:
			System.out.println("28 days");
			break;
		case 4:
			System.out.println("--4");
		case 6:
			System.out.println("--6");
		case 9:
			System.out.println("--9");
		case 11:
			System.out.println("30 days");
			break;
		default:
			System.out.println("Invalid month");
			break;
}

}
	public static void main(String[] args) {
		SumMonthDaysBySwitch2(3);
		SumMonthDaysBySwitch2(2);
		SumMonthDaysBySwitch2(4);
		SumMonthDaysBySwitch2(13);
}	
	
}
```
# 2.
```
public class Test50716 {

	public static void main(String[] args) {
		StringBuilder msg = new StringBuilder("Hello jim!!");
		int loc = 0;
		try {
			for (loc=0 ; loc<12 ; loc++) {
				switch (msg.charAt(loc)) {
				case 'i':
				case 'e':
				case 'o':
					String ucs = Character.toString(msg.charAt(loc)).toUpperCase();
					msg.replace(loc, loc+1, ucs);
					
				}
			}
			
		}catch (Exception e) {
			System.out.println("Out of Limits");
		}

		System.out.println(msg);
	
}

}
```