Golang Programming Examples

Go for Loop

golang

package main

import "fmt"

func main() {
   var b int = 15
   var a int
   numbers := [6]int{1, 2, 3, 5} 

   /* for loop execution */
   for a := 0; a < 10; a++ {
      fmt.Printf("value of a: %d\n", a)
   }
   for a < b {
      a++
      fmt.Printf("value of a: %d\n", a)
   }
   for i,x:= range numbers {
      fmt.Printf("value of x = %d at %d\n", x,i)
   }   
}

Go Select Statement

golang

package main

import "fmt"

func main() {
   var c1, c2, c3 chan int
   var i1, i2 int
   select {
      case i1 = <-c1:
         fmt.Printf("received ", i1, " from c1\n")
      case c2 <- i2:
         fmt.Printf("sent ", i2, " to c2\n")
      case i3, ok := (<-c3):  // same as: i3, ok := <-c3
         if ok {
            fmt.Printf("received ", i3, " from c3\n")
         } else {
            fmt.Printf("c3 is closed\n")
         }
      default:
         fmt.Printf("no communication\n")
   }    
}

Go Expression Switch

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var grade string = "B"
   var marks int = 90

   switch marks {
      case 90: grade = "A"
      case 80: grade = "B"
      case 50,60,70 : grade = "C"
      default: grade = "D"  
   }
   switch {
      case grade == "A" :
         fmt.Printf("Excellent!\n" )     
      case grade == "B", grade == "C" :
         fmt.Printf("Well done\n" )      
      case grade == "D" :
         fmt.Printf("You passed\n" )      
      case grade == "F":
         fmt.Printf("Better try again\n" )
      default:
         fmt.Printf("Invalid grade\n" );
   }
   fmt.Printf("Your grade is  %s\n", grade );      
}

Go nested if statements

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 100
   var b int = 200
 
   /* check the boolean condition */
   if( a == 100 ) {
      /* if condition is true then check the following */
      if( b == 200 )  {
         /* if condition is true then print the following */
         fmt.Printf("Value of a is 100 and b is 200\n" );
      }
   }
   fmt.Printf("Exact value of a is : %d\n", a );
   fmt.Printf("Exact value of b is : %d\n", b );
}

Go if else statement

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 100;
 
   /* check the boolean condition */
   if( a < 20 ) {
      /* if condition is true then print the following */
      fmt.Printf("a is less than 20\n" );
   } else {
      /* if condition is false then print the following */
      fmt.Printf("a is not less than 20\n" );
   }
   fmt.Printf("value of a is : %d\n", a);
}

Go if statement

golang

package main

import "fmt"

func main() {
   /* local variable definition */
   var a int = 10
 
   /* check the boolean condition using if statement */
   if( a < 20 ) {
      /* if condition is true then print the following */
      fmt.Printf("a is less than 20\n" )
   }
   fmt.Printf("value of a is : %d\n", a)
}

Operators Precedence in Go

golang

package main

import "fmt"

func main() {
   var a int = 20
   var b int = 10
   var c int = 15
   var d int = 5
   var e int;

   e = (a + b) * c / d;      // ( 30 * 15 ) / 5
   fmt.Printf("Value of (a + b) * c / d is : %d\n",  e );

   e = ((a + b) * c) / d;    // (30 * 15 ) / 5
   fmt.Printf("Value of ((a + b) * c) / d is  : %d\n" ,  e );

   e = (a + b) * (c / d);   // (30) * (15/5)
   fmt.Printf("Value of (a + b) * (c / d) is  : %d\n",  e );

   e = a + (b * c) / d;     //  20 + (150/5)
   fmt.Printf("Value of a + (b * c) / d is  : %d\n" ,  e );  
}

Go Miscellaneous Operators

golang

package main

import "fmt"

func main() {
   var a int = 4
   var b int32
   var c float32
   var ptr *int

   /* example of type operator */
   fmt.Printf("Line 1 - Type of variable a = %T\n", a );
   fmt.Printf("Line 2 - Type of variable b = %T\n", b );
   fmt.Printf("Line 3 - Type of variable c= %T\n", c );

   /* example of & and * operators */
   ptr = &a	/* 'ptr' now contains the address of 'a'*/
   fmt.Printf("value of a is  %d\n", a);
   fmt.Printf("*ptr is %d.\n", *ptr);
}

Go Assignment Operators

golang

package main

import "fmt"

func main() {
   var a int = 21
   var c int

   c =  a
   fmt.Printf("Line 1 - =  Operator Example, Value of c = %d\n", c )

   c +=  a
   fmt.Printf("Line 2 - += Operator Example, Value of c = %d\n", c )

   c -=  a
   fmt.Printf("Line 3 - -= Operator Example, Value of c = %d\n", c )

   c *=  a
   fmt.Printf("Line 4 - *= Operator Example, Value of c = %d\n", c )

   c /=  a
   fmt.Printf("Line 5 - /= Operator Example, Value of c = %d\n", c )

   c  = 200; 

   c <<=  2
   fmt.Printf("Line 6 - <<= Operator Example, Value of c = %d\n", c )

   c >>=  2
   fmt.Printf("Line 7 - >>= Operator Example, Value of c = %d\n", c )

   c &=  2
   fmt.Printf("Line 8 - &= Operator Example, Value of c = %d\n", c )

   c ^=  2
   fmt.Printf("Line 9 - ^= Operator Example, Value of c = %d\n", c )

   c |=  2
   fmt.Printf("Line 10 - |= Operator Example, Value of c = %d\n", c )
}

Go Bitwise Operators

golang

package main

import "fmt"

func main() {
   var a uint = 60	/* 60 = 0011 1100 */  
   var b uint = 13	/* 13 = 0000 1101 */
   var c uint = 0          

   c = a & b       /* 12 = 0000 1100 */ 
   fmt.Printf("Line 1 - Value of c is %d\n", c )

   c = a | b       /* 61 = 0011 1101 */
   fmt.Printf("Line 2 - Value of c is %d\n", c )

   c = a ^ b       /* 49 = 0011 0001 */
   fmt.Printf("Line 3 - Value of c is %d\n", c )

   c = a << 2     /* 240 = 1111 0000 */
   fmt.Printf("Line 4 - Value of c is %d\n", c )

   c = a >> 2     /* 15 = 0000 1111 */
   fmt.Printf("Line 5 - Value of c is %d\n", c )
}

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