Golang Programming Examples

Go function closure

golang

package main

import "fmt"

func getSequence() func() int {
   i:=0
   return func() int {
      i+=1
	  return i  
   }
}

func main(){
   /* nextNumber is now a function with i as 0 */
   nextNumber := getSequence()  

   /* invoke nextNumber to increase i by 1 and return the same */
   fmt.Println(nextNumber())
   fmt.Println(nextNumber())
   fmt.Println(nextNumber())
   
   /* create a new sequence and see the result, i is 0 again*/
   nextNumber1 := getSequence()  
   fmt.Println(nextNumber1())
   fmt.Println(nextNumber1())
}

Go functions as values

golang

package main

import (
   "fmt" 
   "math" 
)

func main(){
   /* declare a function variable */
   getSquareRoot := func(x float64) float64 {
      return math.Sqrt(x)
   }

   /* use the function */
   fmt.Println(getSquareRoot(9))
}

Go Call by reference

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 100
   var b int = 200

   fmt.Printf("Before swap, value of a : %d\n", a )
   fmt.Printf("Before swap, value of b : %d\n", b )

   /* calling a function to swap the values */
   swap(a, b)

   fmt.Printf("After swap, value of a : %d\n", a )
   fmt.Printf("After swap, value of b : %d\n", b )
}
func swap(x, y int) int {
   var temp int

   temp = x /* save the value of x */
   x = y    /* put y into x */
   y = temp /* put temp into y */

   return temp;
}

Go Call by value

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 100
   var b int = 200

   fmt.Printf("Before swap, value of a : %d\n", a )
   fmt.Printf("Before swap, value of b : %d\n", b )

   /* calling a function to swap the values */
   swap(a, b)

   fmt.Printf("After swap, value of a : %d\n", a )
   fmt.Printf("After swap, value of b : %d\n", b )
}
func swap(x, y int) int {
   var temp int

   temp = x /* save the value of x */
   x = y    /* put y into x */
   y = temp /* put temp into y */

   return temp;
}

Go Calling a Function

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 100
   var b int = 200
   var ret int

   /* calling a function to get max value */
   ret = max(a, b)

   fmt.Printf( "Max value is : %d\n", ret )
}

/* function returning the max between two numbers */
func max(num1, num2 int) int {
   /* local variable declaration */
   var result int

   if (num1 > num2) {
      result = num1
   } else {
      result = num2
   }
   return result 
}

Execute GO Language Online

golang

package main

import "fmt"

func main() {
   fmt.Printf("hello, world\n")
}

goto Statement

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 10

   /* do loop execution */
   LOOP: for a < 20 {
      if a == 15 {
         /* skip the iteration */
         a = a + 1
         goto LOOP
      }
      fmt.Printf("value of a: %d\n", a)
      a++     
   }  
}

Go continue Statement

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 10

   /* do loop execution */
   for a < 20 {
      if a == 15 {
         /* skip the iteration */
         a = a + 1;
         continue;
      }
      fmt.Printf("value of a: %d\n", a);
      a++;     
   }  
}

Go break statement

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 10

   /* for loop execution */
   for a < 20 {
      fmt.Printf("value of a: %d\n", a);
      a++;
      if a > 15 {
         /* terminate the loop using break statement */
         break;
      }
   }
}

Go Nested for Loops

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var i, j int

   for i = 2; i < 100; i++ {
      for j = 2; j <= (i/j); j++ {
         if(i%j==0) {
            break; // if factor found, not prime
         }
      }
      if(j > (i/j)) {
         fmt.Printf("%d is prime\n", i);
      }
   }  
}

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