Go Language - Program to Check Whether a Number is Prime or Not
- Prime numbers are natural numbers that are only divisible by 1 and the number itself.
- A prime number cannot be divided by any other numbers without leaving a remainder.
- An example of a prime number is 17. It can only be divided by 1 and 17, which has only two factors 1 and 5.
- Let's take another example of the number 6, which has more than two factors, i.e 1, 2, 3, and 6. This means 6 is not a prime number.
Example 1. Go Program to check whether the given number is Prime or not
package main
import (
"fmt"
)
func main() {
CheckPrimeNumber(11)
CheckPrimeNumber(1)
CheckPrimeNumber(23)
CheckPrimeNumber(20)
CheckPrimeNumber(-9)
}
func CheckPrimeNumber(number int) {
isPrime := true
if number < 0 {
fmt.Println("Number must be greater than 0")
} else if number == 0 || number == 1 {
fmt.Println(number, "is not a prime number")
} else {
for i := 2; i <= number/2; i++ {
if number%i == 0 {
fmt.Println(number, " is not a prime number")
isPrime = false
break
}
}
if isPrime == true {
fmt.Println(number, "is a prime number")
}
}
}
Output:
Example 2. Go Program to check whether the number from standard input is Prime or not
package main
import (
"fmt"
)
func main() {
var number int
fmt.Println("Enter an integer value : ")
_, err := fmt.Scanf("%d", &number)
if err != nil {
fmt.Println(err)
}
CheckPrimeNumber(number)
}
func CheckPrimeNumber(number int) {
isPrime := true
if number < 0 {
fmt.Println("Number must be greater than 0")
} else if number == 0 || number == 1 {
fmt.Println(number, "is not a prime number")
} else {
for i := 2; i <= number/2; i++ {
if number%i == 0 {
fmt.Println(number, " is not a prime number")
isPrime = false
break
}
}
if isPrime == true {
fmt.Println(number, "is a prime number")
}
}
}
Output:
