Control Statements and Loops
if statement
if condition {
// Statements to execute if
// condition is true
}if…else Statement
if condition {
// Executes this block if
// condition is true
} else {
// Executes this block if
// condition is false
}Nested if Statement
if condition1 {
// Executes when condition1 is true
if condition2 {
// Executes when condition2 is true
}
}if..else..if ladder
if condition_1 {
// this block will execute
// when condition_1 is true
} else if condition_2 {
// this block will execute
// when condition2 is true
}
.
.
. else {
// this block will execute when none
// of the condition is true
}Loops
1. As simple for loop
for initialization; condition; post{
// statements....
}pacakage main
import "fmt"
func main(){
for i := 0; i<4; i++{
fmt.Println("hello world")
}
}
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Output
hello world
hello world
hello world
hello world
2. For loop as Infinite Loop:
for{
// Statement...
}package main
import "fmt"
func main(){
for{
fmt.Println("hello world")
}
}
___________________________________________________________
Output
hello world
hello world
hello world
hello world
.
.
.3. for loop as while Loop:
for condition{
// statement..
}package main
import "fmt"
func main(){
i:= 0
for i<3{
i+=2 // loop executes till i<3 condition is true
}
fmt.Println(i)
}
___________________________________________________________
Output
44. Simple range in for loop:
for i, j:= range rvariable{
// statement..
}package main
import "fmt"
func main() {
numbers := []int{1, 2, 3, 4, 5}
// Using range to iterate over a slice
// i stores the index number of individual number
// num stores the individual number
for i, num := range numbers {
fmt.Printf("Index: %d, Value: %d\n", i, num)
}
}
Switch Statement
In Go, a switch statement is a multiway branch statement that efficiently directs execution based on the value (or type) of an expression.
package main
import "fmt"
func main() {
i := 2
fmt.Print("Write ", i, " as ")
switch i {
case 1:
fmt.Println("one")
case 2:
fmt.Println("two")
case 3:
fmt.Println("three")
default:
fmt.Println("unknown number")
}
}
Multiple expressions in case:
You can have multiple expressions in a single case: package main
import "fmt"
func main() {
char := 'a'
switch char {
case 'a', 'e', 'i', 'o', 'u':
fmt.Println("Vowel")
default:
fmt.Println("Consonant")
}
}Switch with no condition:
A switch statement with no condition is used as an alternative to if-else:
package main
import "fmt"
func main() {
num := 75
switch {
case num > 100:
fmt.Println("Greater than 100")
case num > 50:
fmt.Println("Greater than 50")
default:
fmt.Println("50 or less")
}
}In this example, we use the same day variable but wrapped in an interface{} to demonstrate the type switch.
package main
import "fmt"
func main() {
var day interface{} = 4
switch v := day.(type) {
case int:
switch v {
case 1:
fmt.Println("Monday")
case 2:
fmt.Println("Tuesday")
case 3:
fmt.Println("Wednesday")
case 4:
fmt.Println("Thursday")
case 5:
fmt.Println("Friday")
default:
fmt.Println("Invalid day")
}
default:
fmt.Printf("Unknown type: %T\n", v)
}
}