Process Control in the Java language

Lab environment:jdk1.8.0_111

Process Control in the Java language

• Select structure

1,if-else statements

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When using If,else If,else, the following block of statements is enclosed in {}:

If and else pair use

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If...else the difference between If...else and If...if...if:

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It is known that the former indicates that the program may have an entrance and that there may be an exit, which is bound to be exported in the case of an else clause.

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Known, the latter indicates that the program may have multiple entrances.

Practice

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How to implement a three integer input by the keyboard:

---Import the scanner class outside the class keyword

Import Java.util.Scanner;

Create a Scanner object

Scanner Scanner = new Scanner (system.in);

, get input integer

System.out.print ("NUM1 ="),//print without ln means that the output does not wrap

int i = Scanner.nextint ();//means input an integer

System.out.println ("Output NUM1 is" + NUM1);//This means that the string is added

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Known output as x Is2

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2,switch statements

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The switch statement indicates the meaning of the switches, with the following rules for the switching statement:

->switch (expression), the return value of an expression must be one of the following 6 data types

Byte,short,int,char (JDK1.4)

Enumeration type (JDK5.0 added)

String (JDK7.0 added)

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The value in the->CASE clause must be a constant, and the value of all case clauses should be different

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The->DEFAULT clause is optional and dispensable

Equivalent to the ELSE clause in the IF-ELSE statement

->break statement that executes a case branch, causes the program to jump out of the switch statement block

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Practice

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        class TestSwitch{             public static void main () {                 int a = 3;                 int x = 100;                                  switch (a) {                      case 1:                         x += 5;                         break;                     case 2:                          x += 10;                         break;                     case 3:                          x += 16;                         break;                     case 4:                          x += 34;                         break;                     default:                          x += 100;                         break;                 }             }        } 

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Process Control in the Java language