Java day-04

Program Flow Control
-Judging structure
-Select structure
-Cycle structure

Judging Structure

1. if (conditional expression)
{
Execute the statement;
}

2. if (conditional expression)
{
Execute the statement;
}
Else
{
Execute the statement;
}

3. if (conditional expression)
{
Execute the statement;
}
else if (conditional expression)
{
Execute the statement;
}
.....
Else
{
Execute the statement;
}
When three conditions are set, the value of the first condition is printed by default, and the preceding value is printed by default when two conditions are satisfied;
Execute the program from the top down.

1 Package cn.itcast.test;2  Public classIf_demo {//An example of if3      Public Static voidMain (string[] args) {4         intx=3;5         if(x>1)6         {7System. out. println ("A");8}Else if(x==3)9         {TenSystem. out. println ("B"); One         } A         Else -         { -System. out. println ("C"); the         }

 -          -         intweek=2; -         if(week==1) +System. out. println (week+"Representative Monday"); -         if(week==2) +System. out. println (week+"Representative Tuesday");

 A         intMonth= -; at         if(month==3|| month==4|| month==5) -System. out. println (month+"Spring"); -         Else if(month==6|| month==7|| month==8) -System. out. println (month+"Summer"); -         Else if(month==9|| month==Ten|| month== One) -System. out. println (month+"Autumn"); in         Else if(month== A|| month==1|| month==2) -System. out. println (month+"Winter"); to         Else +System. out. println ("could not find the corresponding season");

 -          the          intMonth=1; *          if(month>3& month<5) $System. out. println (month+"month corresponds to spring");Panax Notoginseng          Else if(month>5& month<9) -System. out. println (month+"month corresponds to summer"); the          Else if(month>9& month< A) +System. out. println (month+"month corresponds to autumn"); A          Else if(month> A& month< the) theSystem. out. println (month+"month corresponds to winter"); +          Else  -System. out. println (month+"there is no corresponding season."); $     } $}

Select structure
switch (expression)
{
Case takes value 1:
Execute the statement;
Break
Case takes value 2:
Execute the statement;
Break
......
Default
Execute the statement;
break;//can be omitted
}
Switch statement features:
-only four types of statements are selected: Byte, short, int, char
-Case with default no order, first case executed, no matching case execution default
-End Switch statement: Encounter break, execute to switch statement end
-If the matching case or default does not have a corresponding break, the program will continue to execute the executed statement, knowing that a break or switch end is encountered

1 Package cn.itcast.test;2  Public classSwitch_demo {3      Public Static voidMain (string[] args) {4         intx=3;5         Switch(x+1)6         {7          Case 3:8System. out. println ("Hello");9              Break;Ten          Case 5: OneSystem. out. println ("Hi there! "); A              Break; -             default: -System. out. println ("did not find the corresponding"); the         }

 -         intNUM1 = -, num2 =4; -         CharOPR ='*'; -         Switch(OPR) +         { -          Case '+': +System. out. println (num1+num2); A              Break; at          Case '-': -System. out. println (num1-num2); -              Break; -          Case '*': -System. out. println ("num1*num2="+num1*num2); -              Break; in          Case '/': -System. out. println ("num1/num2="+num1/num2); to              Break; +             default: -System. out. println ("the corresponding operator could not be found"); the              Break;//can omit *         } $     }Panax Notoginseng}

Java day-04