? ?? ???, ???, ??? ? ???? ??? ??? ??? ?? ???? java? ?? ?? ??? ?????. ?? ??? ??? ??? ????.

?? ??: "java ??? ????"

Process control

JAVA ?? ? ??

Input

? ?? ?? ?? :

?? 1: java.util.Scanner
??? ??? ????:

public?class?a?{
????public?static?void?main(String[]?args)?{
????????var?sc?=?new?Scanner(System.in);
????????System.out.println("請輸入姓名：");
????????String?name?=?sc.nextLine();
????????System.out.printf("%n歡迎你：%s",?name);
????}}

Scanner ??? ???? "Please enter your name:"? ???? ?? ???? ???? name? ???? "%nWelcome %s"? ?????. %n? ??? ?????. %s? ??? ?????.

Result:

?? 2: JOptionPane ?? ??? ???? ??? ?? null

public?class?a?{
????public?static?void?main(String[]?args)?{
????????String?w?=?JOptionPane.showInputDialog("請輸入詞匯：");
????????System.out.println(w);
????}}

Result:

Output

? ???.

? ?? ?? ?? ??
?? 1: System.out.print(); ??? ??
?? 2: System.out.println(); ??? ?? ? ??
?? 3: System.out.printf () ;??? ???? ??

?? ??:

? ?? ??? ??? ?? ?? ?????.

public?class?a?{
????public?static?void?main(String[]?args)?{
????????int?w?=?1;
????????int?a?=?2;
????????System.out.print(w);
????????System.out.print(a);
????}}

??:

? ?? ?? ??? ?????

public?class?a?{
????public?static?void?main(String[]?args)?{
????????int?w?=?1;
????????int?a?=?2;
????????System.out.println(w);
????????System.out.println(a);
????}}

??:

? ?? ??? ??
%d? int ?? ??? ?????. ?, ? ?? %d? w ??? ??? ? ?? %d? a

public?class?a?{
????public?static?void?main(String[]?args)?{
????????int?w?=?1;
????????int?a?=?2;
????????System.out.printf("w=%d?a=%d",?w,?a);
????}}

??? ????. ??:

branch ?

if else

if() ?? ?? ??? ??? ?? true? ????, ??? false? ?????.
else? ??? ?? ??? ?????.

public?class?a?{
????public?static?void?main(String[]?args)?{
???????if?(1>2){
???????????System.out.println("A");
???????}else?{
???????????System.out.println("B");
???????}
????}}

?? ??? ??? ????. ??? ????: ?? ??? ??? ?? ???? ???? ?? ?? true? ? ????, ??? ??? else

public?class?a?{
????public?static?void?main(String[]?args)?{
????????if?(1?>?2)?{
????????????System.out.println("A");
????????}?else?if?(1?>?0)?{
????????????System.out.println("B");
????????}?else?{
????????????System.out.println("C");
????????}
????}}

? ?????.switch case default

switch ?? ?? ??? ?
(w) ?? ?? w? ????, Case ?? ??? w? ???? ???. w? ?? Case ??? ?? ???? ?? Case? ?? ?????. Break? ?? ??? ????? ??? ??? ?? ??? ??? ??? ?????. ???? ??? ?? ??

public?class?a?{
????public?static?void?main(String[]?args)?{
????????int?w=1;
????????String?wk?=?"";
????????switch?(w)?{
????????????case?2:
????????????????wk?=?"星期一";
????????????????break;
????????????case?3:
????????????????wk?=?"星期二";
????????????????break;
????????????case?4:
????????????????wk?=?"星期三";
????????????????break;
????????????case?5:
????????????????wk?=?"星期四";
????????????????break;
????????????case?6:
????????????????wk?=?"星期五";
????????????????break;
????????????case?7:
????????????????wk?=?"星期六";
????????????????break;
????????????default:
????????????????wk?=?"星期日";
????????????????break;
????????}
????????System.out.println(wk);
????}}

??:

?? ?

for

for (int i = 0; i 5? ? ??? ?????.

public?class?a?{
????public?static?void?main(String[]?args)?{
????????for?(int?i?=?0;?i???: 

for in

for in? ?? ????? ??? ???? ? ?????. ??? ???? ?????.

public?class?a?{
????public?static?void?main(String[]?args)?{
????????int[]?a?=?{1,?2,?3,?4,?5};
????????for?(int?i?:?a)?{
????????????System.out.println(i);
????????}
????}}

i? ??? ???? ?? a? ?????. ?? ??? ?? a[0], a[1]a[2], a[3]a[4]

while do while

while? ?? ???? ?? ?????( ??) {}

??? ???? ???? ????, ??? ??? ?????.
• 
  

public?class?a?{
????public?static?void?main(String[]?args)?{
????????int?i?=?0;
????????while?(i???: 

do while

while? ?? do while? ? ? ???? ?????

public?class?a?{
????public?static?void?main(String[]?args)?{
????????int?i?=?0;
????????do?{
????????????i++;
????????????System.out.println(i);

????????}?while?(i?

????? ??? ?? ??? ? ?????. ??? ?? i

??:

break continue

break; 終止當(dāng)前循環(huán)語句
continue; 結(jié)束這一次循環(huán)，立即準(zhǔn)備開啟下一次循環(huán)

int?i?=?0;while?(++i??10)?break;}

當(dāng)i被2整除就跳過這一次，進(jìn)行下一次循環(huán)。當(dāng)i大于10就結(jié)束循環(huán)。

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