This is a creation in Article, where the information may have evolved or changed. This is the 8th chapter of our [Golang Series Tutorial] (/SUBJECT/2). If is a conditional statement. The syntax for the IF statement is ' goif condition {} ' if ' condition ' is true, then the code between ' {' and '} ' is executed. Unlike other languages, such as the C language, the ' {} ' in the Go language is necessary, even if there is only one statement between ' {} '. The IF statement also has an optional ' else if ' and ' Else ' section. There can be any number of ' else if ' between goif condition {} else if condition {} else {} ' if-else statements. The order of conditional judgments is from top to bottom. If the ' if ' or ' else if ' condition determines that the result is true, the corresponding code block is executed. If no condition is true, then the ' Else ' code block is executed. Let's write a simple program to detect whether a number is odd or even. "' Gopackage mainimport (" FMT ") func main () {num: = if num% 2 = = 0 {//checks If number is even fmt. Println ("The number is even")} else {fmt. Println ("The number is odd")}} "[Run Program Online] (https://play.golang.org/p/vWfN8UqZUr) ' if num%2 = = 0 ' statement detects whether the remainder of NUM Fetch 2 is zero. If it is zero then the printout "the number is even", if not zero, prints out "the number is odd". In the above program, the printout is ' the number is even '. The ' if ' has another form, which contains a ' statement ' optional statement part that runs before the condition is judged. Its syntax is ' ' ' goif statement; Condition {} "let's rewrite the program and use the syntax above to find whether the number is even or odd." "' Gopackage mainimport (" FMT ") func main () {if num: = ten; num% 2 = = 0 {//checks If number IS even FMT. PRINTLN (num, "is even")} else {fmt. PRINTLN (num, "is Odd")}} "[Online Run Program] (HTTPS://PLAY.GOLANG.ORG/P/_X9Q4MWR4S) in the above program, ' Num ' is initialized in ' if ' statement, ' num ' can only be from ' if ' and ' Else ' access. That means ' num ' is limited to the ' if ' Else ' code block. If we try to access ' num ' from other external ' if ' or ' else ', the compiler will not pass. Let's write another program that uses ' else if '. "' Gopackage mainimport (" FMT ") func main () {num: = if num <= (FMT). Println ("number is less than or equal")} else if num >= && num <= {fmt. Println ("number is between and")} else {fmt. Println ("number is greater than 100")}} "[Running Program Online] (Https://play.golang.org/p/Eji7vmb17Q) in the above program if ' else if Num >= && num <= 100 ' is true, the program will output ' number is between and 100 '. [Get free Golang tools] (HTTPS://APP.MAILERLITE.COM/WEBFORMS/POPUP/P8T5T8) # # # A note that the ' Else ' statement should be in the same row after the curly brace '} ' of the ' if ' statement. If not, the compiler will not pass. Let's use the following procedure to understand it. "' Gopackage mainimport (" FMT ") func main () {num: = if num% 2 = = 0 {//checks If number is even fmt. Println ("The number is even")} else {fmt. Println ("the Number is odd ")}}" [Running Program Online] (https://play.golang.org/p/RYNqZZO2F9) in the above program, the ' Else ' statement does not start with the same line as the ' if ' statement after the end of '} '. Instead, start with the next line. This is not allowed. If you run this program, the compiler will output an error, "' Main.go:12:5: Syntax error:unexpected else, expecting} ' is an error because the semicolon of the go language is automatically inserted. You can read the semicolon insertion rule [https://golang.org/ref/spec#Semicolons] (https://golang.org/ref/spec#Semicolons) here. In the Go language rule, it specifies that a semicolon is inserted after '} ' if this is the final tag of the line. Therefore, the '} ' after the IF statement will automatically insert a semicolon. In fact our program has become "goif num%2 = = 0 {fmt. Println ("The number is even")}; Semicolon inserted by Goelse {fmt. Println ("The number is odd")} ' "' semicolon inserted after. You can see from the code snippet above that the third line has a semicolon inserted. Because ' if{...} else {...} ' is a separate statement, it should not appear in the middle of a semicolon. Therefore, you need to place the ' else ' statement on the same line after '} '. I have rewritten the program and moved the else statement to the end of the IF statement after '} ' to prevent automatic insertion of semicolons. "' Gopackage mainimport (" FMT ") func main () {num: = if num%2 = = 0 {//checks If number is even fmt. Println ("The number is even")} else {fmt. Println ("The number is odd")}} "[Running Program Online] (Https://play.golang.org/p/hv_27vbIBC) Now the compiler will be happy, and so are we? This chapter of the tutorial is over, thank you for your reading and welcome any comments and feedback. * * Previous Tutorial-[Package (Packages)] (https://studygolang.com/articles/11893) * * * * Next tutorial-[loop] (https://studygolang.com/articles/11924) * *
via:https://golangbot.com/if-statement/
Author: Nick Coghlan Translator: Dingo1991 proofreading: Rxcai
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