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Golang basic: Condition

shellrean profile image ShellRean ・2 min read

When you are in a crossroad and you choose to turn right and you see the pizza restaurant. that is condition and what your decision and that you get.

Let's we write how go write their code

Write Condition: if

Our decision is to turn right and we see the pizza restaurant.

package main

import "fmt"

func main() {

  turn := "right"

  if turn == "right" {
    fmt.Println("Pizza restuarant")
  }
}

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we use if to make condition if the value is true then the block {...} will be execute.

turn == "right" will return bool type true or false

package main

import "fmt"

func main() {

  if true {
    fmt.Println("Always True")
  }
}
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Write Condition: else

Okay it just turn right but in the other side we see school how we go there. we could use else

package main

import "fmt"

func main() {

  turn := "left"

  if turn == "right" {
    fmt.Println("Pizza restaurant")
  } else {
    fmt.Println("School")
  }
}
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It will check is turn equal with "right" if not it will go to else and execute block else {...}

else have to write as } else { or you will get error compiler

package main

import "fmt"

func main() {

  turn := "right"

  // It will get error compiler
  if turn == "right" {
    fmt.Println("Pizza restaurant")
  } 
  else {
    fmt.Println("School")
  }
}
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Write Condition: elseif

But wait no it is not other side, I want more specific what if I turn somewhere.

package main

import "fmt"

func main() {

  turn := "left"

  if turn == "right" {
    fmt.Println("Pizza restaurant")
  } else if(turn == "left") {
    fmt.Println("Gas station")
  } else {
    fmt.Println("School")
  }
}
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There more operator logic you can use on if condition

Operator Mean
== equal
!= not equal
! not
&& and
< less than
> greater than
<= less than or equal
>= greater than or equal

Is the data type just string value, NO. you can give condition with any data type

package main

import "fmt"

func main() {

  if 17 < 20 {
    fmt.Print("17 is less than 20")
  } else {
    fmt.Print("17 is greater than 20")
  }
}
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Write condition: Switch

But is more complex imagine you look at street sign and what you can see? yeah the direction of the road.
you can convert if condition we have wrote before to switch condition

package main

import "fmt"

func main() {

  turn := "right"

  switch(turn) {
  case "right" :
    fmt.Println("Pizza restaurant")
  case "left" :
    fmt.Println("School")
  default: 
    fmt.Println("Gas station")
  }
}
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switch is a function that can write condition with a variable the example use turn variable, and the condition actually use == equal.

case will check is value of turn variable is equal to "right". and if it not equal then will check the case "left".

if all conditions were not equal, so default will run.

don't forget to add : at the end of case or you will get error compiler.

Conclusion

We have created condition with two different functions and when we use if condition and when we use switch condition is up to you, but it look at the complexity and the logic in that condition.

if condition, you can give more logic !, !=, == , &&, || but in switch you cannot use them.

Question:
Write these line in if and switch conditions
if your age is 17 you have to get milk shake license
if not you can't get milk shake license

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