Golang Program to Find the Sum of N Numbers using Recursion

In this tutorial, we are going to learn how to find the sum of N Numbers using Recursion in Golang programming language.

A Recursion is where a function calls itself by direct or indirect means. Every recursive function has a base case or base condition which is the final executable statement in recursion and halts further calls.

Below are two examples showing the two different type of recursion: direct and indirect.

Find the Sum of N Numbers by Direct Recursion Method

Syntax

Syntax for direct recursion
func recursion() {
   recursion()
}
func main() {
   recursion();
}

Algorithm

• Step 1 − Import the package fmt

• Step 2 − Create the function sum()

• Step 3 − We will use an if...else conditional statement

• Step 4 − Start the function main()

• Step 5 − Initialize the integer variable

• Step 6 − Call the function sum()

• Step 7 − Print the result on the screen using fmt.Printf()

Example

Golang Program Code to Find the Sum of N Numbers using Recursion by using Direct Recursion Method.

// GOLANG PROGRAM TO FIND THE SUM OF
// N NUMBERS USING RECURSION
package main

// fmt package provides the function to print anything
import "fmt"

// defining the function with a parameter of int
// type and have a return type int
func sum(n int) int {

   // this is the base condition
   // if n is equal to 0
   if n == 0 {

   // function will return 0 and end the recursive function
   return 0
   } else {
      // recursive call to itself
      return n + sum(n - 1)
   }
}

// start the main() function
func main() {

   // Declare and initialize integer variable
   number := 25
   fmt.Println("Sum of first n numbers using recursion in Golang Program")
   fmt.Printf("Sum of the first %d numbers is %d", number, sum(number))
   // Prints the final result
}

Output

Sum of first n numbers using recursion in Golang Program
Sum of the first 25 numbers is 325

Description of the Code

• In the above program, we first declare the package main

• We imported the fmt package that includes the files of package fmt

• Next we create a function sum () to find sum of n numbers using recursion technique

• We will use an if...else conditional statement which allows you to execute one block of code if the specified condition is true and another block of code if the condition is false.

• If n is equal to 0, function will return 0 and end the recursive function

• Else function will recursive call to the function itself and return (n + sum(n-1))

• Now start the function main()

• Next initialize the integer variable number

• Now calling the sum() function

• And finally printing the result on the screen using fmt.Printf().

Find the Sum of N Numbers by Indirect Recursion Method

Syntax

func recursion_1() {
   recursion_2()}
func recursion_2(){
   recursion_1()}
func main() {
   recursion_1();
}

Algorithm

• Step 1 − Import the package fmt

• Step 2 − Create the function sum ()

• Step 3 − We will use an if...else conditional statement

• Step 4 − Create the function sumofn ()

• Step 5 − Recursive call to the function sum() indirectly

• Step 6 − Start the function main()

• Step 7 − Initialize the integer variable number

• Step 8 − Call the function sum()

• Step 9 − Print the result on the screen using fmt.Printf()

Example

Golang Program Code to Find the Sum of N Numbers using Recursion by using Indirect Recursion Method.

// GOLANG PROGRAM TO FIND THE SUM OF
// N NUMBERS USING RECURSION
package main

// fmt package provides the function to print anything
import "fmt"

// defining the function with a parameter of int
// type and have a return type int
func sum(n int) int {

   // this is the base condition
   // if num is equal to 0
   if n == 0 {

      // function will return 0 and end the recursive function
      return 0
   } else {

      // recursive call to sumofn ()
      return n + sumofn(n - 1)
   }
}

// defining the function with a parameter of int
// type and have a return type int
func sumofn(n int) int {

   // this is the base condition
   // if num is equal to 0
   if n == 0 {

      // function will return 0 and end the recursive function
      return 0
   } else {

      // recursive call to function sum ()
      return n + sum(n - 1)
   }
}

// start the main() function
func main() {

   // Declare and initialize integer variable
   number := 55
   fmt.Println("Sum of first n numbers using recursion in Golang Program")

   // calling the function sum()
   fmt.Printf("Sum of first %d numbers is %d", number, sum(number))

   // Prints the final result
}

Output

Sum of first n numbers using recursion in Golang Program
Sum of first 55 numbers is 1540

Description of the Code

• In the above program, we first declare the package main

• We imported the fmt package that includes the files of package fmt

• Next we create a function natural1() to find sum of natural numbers using recursion technique

• Next we create a function sum () to find sum of n numbers using recursion technique

• We will use an if...else conditional statement which allows you to execute one block of code if the specified condition is true and another block of code if the condition is false.

• If n is equal to 0, function will return 0 and end the recursive function

• Else function will recursive call to the function sumofn() and return (n + sumofn(n-1))

• Next we create a function sumofn () and similarly like the above function make a recursive call to the function sum() and return (n + sum(n-1))

• Now start the function main()

• Next initialize the integer variable number

• Now calling the first function sum()

• And finally printing the result on the screen using fmt.Printf().

Conclusion

In the above two examples we have successfully compiled and executed the Golang program code to find the sum of n number using recursion technique. We have shown direct and indirect type of recursion method. In the first example we have shown direct recursion method and in the second example we have shown indirect recursion method.