### Recursion in Go Language

• date 6th September, 2022 |
• by Prwatech |

# Recursion is different types:

1. Direct Recursion : Program to illustrate the Fibonacci series
```package main
import "fmt"

func fib(i int) int {

if i == 0 {
return 1
}
if i == 1 {
return 1
}
return fib(i-1) + fib(i-2)
}
func main() {
var i int
for i = 0; i < 10; i++ {
fmt.Printf("%d \n", fib(i))

}
}
```

Output :

```PS C:\GO_Language\recursion> go run recursion.go
1
1
2
3
5
8
13
21
34
55
```

2. Indirect Recursion:  Program to illustrate indirect recursion between two functions.
```package main
import "fmt"

func print_one(n int) {
if n >= 0 {
fmt.Println("In first function:", n)
print_two(n - 1)
}
}

func print_two(n int) {

if n >= 0 {
fmt.Println("In second function:", n)
print_one(n - 1)
}
}

func main() {
print_one(10)
print_one(-1)
}
```

Output :

```PS C:\GO_Language\recursion> go run indirect_re.go

In first function: 10
In second function: 9
In first function: 8
In second function: 7
In first function: 6
In second function: 5
In first function: 4
In second function: 3
In first function: 2
In second function: 1
In first function: 0
```

3. Tail recursion :  Golang program to illustrate the concept of tail recursion
```package main

import (
"fmt"
)

// tail-recursive function to print all numbers from n to 1
func print_num(n int) {

// if a number is still  positive, print it and call the function with the decremented value
if n > 0 {
fmt.Println(n)

//  last statement in  the recursive function tail recursive call
print_num(n - 1)
}
}

// main function
func main() {

// passing a positive number, prints 5 to 1
print_num(5)
}
```

Output :

```PS C:\GO_Language\recursion> go run rec3.go
5
4
3
2
1
```

4. Head Recursion : Golang program to illustrate the concept of head recursion
```package main

import (
"fmt"
)

func print_num(n int) {

if n > 0 {
print_num(n - 1)
fmt.Println(n)
}
}
func main() {
print_num(5)
}
```

Output :

```PS C:\GO_Language\recursion> go run rec4.go
1
2
3
4
5
```

5. Infinite Recursion :Infinite repetition occurs when the second condition is not followed. , There’s an infinite recursion in action here
```package main

import (
"fmt"
)

func print_hello() {
fmt.Println("Prwatech")
print_hello()
}
func main() {
print_hello()
}
```

Output :

```PS C:\GO_Language\recursion> go run rec5.go
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech
Prwatech

exit status 0xc000013a
```

### Quick Support  