Find Product of Two Numbers Using Recursion in Go

The product of two numbers is the result you get when you multiply them together. So 15 is the product of 3 and 5 and 22 is the product of 2 and 11 and so on.

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.

Example-1: Golang Program Code to Find The Product of Two Numbers Using Recursion by Using The 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 product().

• STEP 3 ? We will use an if...else conditional statement.

• STEP 4 ? Start the function main().

• STEP 5 ? Initialize the integer variables.

• STEP 6 ? Call the function product().

• STEP 7 ? Print the result on the screen using fmt.Printf().

Example

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

func product(n int, m int) int {
   // if n less than m
   if n < m {
      return product(m, n)
   } else {
      // if m is not equal to 0      
      if (m != 0) {
         // recursive call to itself 
         return (n + product(n, m-1))
      } else {
         return 0
      }
   }
}
// Start the function main()
func main() {
  // Declare and initialize integer variables  
   var a int
   var b int
   var c int
   a = 4
   b = 15
   fmt.Println("The N1=",a,"\nThe N2 =",b)
   c = product(a, b)

   fmt.Printf("The product of two numbers: %d\n", c)
}

Output

The N1= 4 
The N2 = 15
The product of two numbers: 60

Description

• 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 product() to find the product of two numbers using the 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 less than m, the function will return the product(m, n) and end the recursive function.

• And if m is not equal to 0, then the function will recursive call to the function itself and return (n + product(n, m-1)).

• Now start the function main ().

• Next initialize the integer variables a and b which corresponds to the two numbers whose product has to be found. An integer c corresponds to the final result.

• Now call the product () function

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

Example-2 to Find The Product of Two Numbers Using Recursion by Using Indirect Recursion Method

Syntax

Syntax for indirect recursion
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 product_1().

• STEP 3 ? We will use if...else conditional statement.

• STEP 4 ? Create the function product_2().

• STEP 5 ? Recursive call to the function product_1() indirectly.

• STEP 5 ? Start the function main().

• STEP 6 ? Initialize the integer variables x, y and z.

• STEP 7 ? Call the function product_1().

• STEP 8 ? Print the result on the screen using fmt.Printf().

Example

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 product_1(n int, m int) int {
   
   // this is the base condition
    // if n less than m
   if n < m {
      return product_2(m, n)
   } else {
      // if m is not equal to 0      
      if (m != 0) {
         // recursive call to the second function product_2()
         return (n + product_2(n, m-1))
      } else {
         return 0
      }
   }
}
func product_2(n int, m int) int {
   
   // if n less than m
   if n < m {
      return product_1(m, n)
   } else {
      // if m is not equal to 0      
      if (m != 0) {
         // recursive call to the first function product_1() 
         return (n + product_1(n, m-1))
      } else {
         return 0
      }
   }
}
func main() {
  // Declare and initialize integer variable  
   var x int
   var y int
   var z int
   x = 11
   y = 15
   fmt.Println("The N1=",x,"\nThe N2 =",y)
   z = product_1(x, y)
 
   fmt.Printf("The product of two numbers: %d\n", z)
}

Output

The N1= 11 
The N2 = 15
The product of two numbers: 165

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 product_1() to find the product of two numbers using the 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 less than m, the function will return the product (m, n) and end the recursive function.

• And if m is not equal to 0, then the function will recursively call to the second function product_2() indirectly and return (n + product(n, m-1)).

• Next we create a function product_2 () and similarly to the above function make a recursive call to the function product_1() and return (n + product_1(n, m-1)).

• Now start the function main().

• Next initialize the integer variables x and y which correspond to the two numbers whose product has to be found. And integer z corresponds to the final result.

• Now calling the first function product_1().

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