Home » Golang » Golang Find Output Programs

Golang Structures | Find Output Programs | Set 2

This section contains the Golang structures find output programs (set 2) with their output and explanations.
Submitted by Nidhi, on October 11, 2021

Program 1:

package main

import "fmt"

type Sample struct {
	Num1 int
	Num2 int
	Num3 int
}

func main() {
	s1 := Sample{Num1: 100, Num2: 200, Num3: 300}
	s2 := Sample{Num1: 400, Num2: 500, Num3: 600}
	s3 := Sample{Num1: 700, Num2: 800, Num3: 900}

	fmt.Println("Size of s1: ", Sizeof(s1))
	fmt.Println("Size of s2: ", Sizeof(s2))
	fmt.Println("Size of s3: ", Sizeof(s3))
}

Output:

./prog.go:16:30: undefined: Sizeof
./prog.go:17:30: undefined: Sizeof
./prog.go:18:30: undefined: Sizeof

Explanation:

The above program will generate syntax errors because we used Sizeof(). Here we need to import unsafe package. The correct program is given below,

package main

import "fmt"
import "unsafe"

type Sample struct {
	Num1 int
	Num2 int
	Num3 int
}

func main() {
	s1 := Sample{Num1: 100, Num2: 200, Num3: 300}
	s2 := Sample{Num1: 400, Num2: 500, Num3: 600}
	s3 := Sample{Num1: 700, Num2: 800, Num3: 900}

	fmt.Println("Size of s1: ", unsafe.Sizeof(s1))
	fmt.Println("Size of s2: ", unsafe.Sizeof(s2))
	fmt.Println("Size of s3: ", unsafe.Sizeof(s3))
}

/*
Output:
Size of s1:  24
Size of s2:  24
Size of s3:  24
*/

---

Program 2:

package main

import "fmt"
import "unsafe"

type Sample struct {
	Num1 int
	Num2 int
	Num3 int
}

func main() {
	s1 := Sample{Num1: 100, Num3: 300}
	s2 := Sample{Num3: 300, Num1: 100}
	s3 := Sample{Num2: 200}

	fmt.Println("Size of s1: ", unsafe.Sizeof(s1))
	fmt.Println("Size of s2: ", unsafe.Sizeof(s2))
	fmt.Println("Size of s3: ", unsafe.Sizeof(s3))
}

Output:

Size of s1:  24
Size of s2:  24
Size of s3:  24

Explanation:

In the above program, we created a structure Sample that contains Num1, Num2, Num3 members. Then we created the objects of the Sample structure and initialized them partially in the main() function.

After that, we printed the size of objects.

---

Program 3:

package main

import "fmt"
import "unsafe"

type Sample struct {
	Num1   int
	Num2   int
	Num3   int
}

func main() {
    var arr (2)Sample
    
    arr[0].Num1 = 100
    arr[0].Num2 = 200
    arr[0].Num3 = 300
    
    arr[1].Num1 = 100
    arr[1].Num2 = 200
    arr[1].Num3 = 300
    
    fmt.Println("Size of arr[0]: ", unsafe.Sizeof(arr[0]))
    fmt.Println("Size of arr[1]: ", unsafe.Sizeof(arr[1]))
}

Output:

./prog.go:13:14: syntax error: unexpected literal 2, expecting type

Explanation:

The above program will generate a syntax error because we did on declared array properly. The correct declaration is given below,

var arr [2]Sample

---

Program 4:

package main

import "fmt"

// Declaration of structure
type Sample struct {
	num1   int
	Nested struct {
		num2 int
	}
}

func main() {
	var obj Sample

	obj.num1 = 10
	obj.Nested.num2 = 20

	fmt.Printf("Num1  : %d", obj.num1)
	fmt.Printf("\nNum2  : %d", obj.Nested.num2)
}

Output:

Num1  : 10
Num2  : 20

Explanation:

In the above we created a structure Sample, it contains a nested structure nested. In the main() function, we created object obj of structure Sample and initialized values. After that, we printed the result.

---

Program 5:

package main

import "fmt"

func main() {
	type MyType string
	var str MyType = "Hello World"

	fmt.Println("message: ", str)
}

Output:

message:  Hello World

Explanation:

In the above program, we created the alias name of the data-type string using the type keyword. Then we created a string variable str initialized with "Hello World". After that, we printed the str variable.

Golang Find Output Programs »

---