in Go (Golang), control flow is managed using several fundamental constructs, including conditionals (if, else), loops (for), and switch statements. Here's an overview of how these constructs work in Go:
- Conditionals: if, else, else if In Go, if statements are used to execute code based on a condition. Unlike some other languages, Go doesn't require parentheses around the condition. However, the curly braces {} are mandatory.
Basic Statement
package main
import "fmt"
func main() {
age := 20
if age >= 18 {
fmt.Println("You are an adult.")
}
}
'if-else statement' Example
`package main
import "fmt"
func main() {
age := 16
if age >= 18 {
fmt.Println("You are an adult.")
} else {
fmt.Println("You are not an adult.")
}
}
`
'if-else if-else' Statement:
package main
import "fmt"
func main() {
age := 20
if age >= 21 {
fmt.Println("You can drink alcohol.")
} else if age >= 18 {
fmt.Println("You are an adult, but cannot drink alcohol.")
} else {
fmt.Println("You are not an adult.")
}
}
2.Loops: for
Go uses the 'for' loop for all looping needs; it does not have a 'while' or loop
basic 'for' loop:
package main
import "fmt"
func main() {
for i := 0; i < 5; i++ {
fmt.Println(i)
}
}
'for' as a 'while' loop:
package main
import "fmt"
func main() {
i := 0
for i < 5 {
fmt.Println(i)
i++
}
}
Infinite Loop:
package main
func main() {
for {
// This loop will run forever
}
}
'for' loop with 'range':
This is often used to iterate over slices,arrays,maps or strings.
package main
import "fmt"
func main() {
numbers := []int{1, 2, 3, 4, 5}
for index, value := range numbers {
fmt.Println("Index:", index, "Value:", value)
}
}
- Switch Statement Go The 'Switch' statement in Go is used to select one of many code blocks to be executed.Go 'switch'is more powerful than in some other languages and can be used with any type of value, not just integers.
Basic 'switch'
package main
import "fmt"
func main() {
day := "Monday"
switch day {
case "Monday":
fmt.Println("Start of the work week.")
case "Friday":
fmt.Println("End of the work week.")
default:
fmt.Println("Midweek.")
}
}
Switch with multiple expressions in a case:
package main
import "fmt"
func main() {
day := "Saturday"
switch day {
case "Saturday", "Sunday":
fmt.Println("Weekend!")
default:
fmt.Println("Weekday.")
}
}
A switch with no expression acts like a chain of if-else statements.
package main
import "fmt"
func main() {
age := 18
switch {
case age < 18:
fmt.Println("Underage")
case age >= 18 && age < 21:
fmt.Println("Young adult")
default:
fmt.Println("Adult")
}
}
- Defer, panic and recover
package main
import "fmt"
func main() {
defer fmt.Println("This is deferred and will run at the end.")
fmt.Println("This will run first.")
}
Panic And Recover
package main
import "fmt"
func main() {
defer func() {
if r := recover(); r != nil {
fmt.Println("Recovered from panic:", r)
}
}()
fmt.Println("About to panic!")
panic("Something went wrong.")
}
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