JavaScript base -6 JavaScript branching structure (if, if-else, else if, switch-case)

First, Process Control Overview

Process Control of the program

-Program = data + algorithm

-Any complex program algorithm can be implemented by "order", "branch", "Loop" three basic program logic combinations

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Overview of branching structures

-The program can execute certain statements selectively in different situations during the running process

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Second, if statement

Execution logic for an if statement

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If statement flowchart

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-A Boolean value is required by default in the IF decision

-If the value that appears is not a Boolean type, it is automatically converted

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If statement block do not omit ' {} '

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Third, If-else statement

Execution logic for IF-ELSE statements

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Iv. else If statement

If-else Statement Nesting

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Else if statement execution logic

-in fact, the else if structure is a simple way to do if else nesting

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V. Switch-case statements

Switch-case Statement Execution logic

-The Switch-case statement is a special per-point structure that can be executed from different program entrances depending on the value of an expression

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Switch-case and break joint use

-Usually the case1, Case2 、...、 CaseN correspond to a completely different operation and can be used in conjunction with the break statement, exit the switch block after executing the complete statement, do not proceed with the following statement,

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Switch-case Statements for branching

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Advantages of Switch-case

-Switch-case is often used in conjunction with break statements to implement branching functions

-The main difference between Switch-case and if-else when implementing branching functions is that

-Switch...case ... The structure is clearer and more efficient, but it is generally used only to specify that a variable is equal to a specific value within a range

Summary: This chapter covers the basics of JavaScript -6 JavaScript branching structure (if, if-else, else if, switch-case)

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JavaScript base -6 JavaScript branching structure (if, if-else, else if, switch-case)