 # GO Program to check prime number

For a better understanding of this example, we always recommend you to learn the basic topics of Golang programming listed below:

## What is a prime number?

A prime number is a whole number that is only divisible by 1 and itself
Example: 2, 3, 5, 7 etc.

## How to check prime number

The simplest way to check whether the given number is a prime number is find the factors of the given number. If the number displays more than two factors, then it is not a prime number. If the given number has only two factors that is 1 and the number itself then the number is a prime number.

## How to check prime numbers in the GO Program

2 is the only even prime number. Here we are using` for loop` that starts at 2 and ends at the number/2.
Syntax for f`or loop`

``````
for    initializer; condition;   incrementor {
}
```
```

Within the` for loop `we used the` if` statement to examine the number divisible by the iterator value. If the condition is true then increment the count value and exit the loop. After the` for loop,` we used the` if else` statement to check the count value is equal to 0 and the number not equal to 1.

syntax for `if...else`

``````
if condition {
//do some instructions
}else {
//do some instructions
```
```

If the condition is true then it is a prime number otherwise not a prime.

## ALGORITHM

STEP 1: Import the package fmt

STEP 2: Start function main()

STEP 3: Declare the variable num, count

STEP 4: Read the number num using `fmt.Scanfln()`

STEP 5:Initialise integer count=0

STEP 6: Use for loop as (for i := 2; i < num/2; i++)

STEP 7: Check num%i == 0 and count++ in the loop

STEP8: Use `If else` statement (if count == 0 && num != 1)

STEP9: If true, it is a Prime, otherwise not a Prime number.

## GO Source Code

```                                          ```package main
import "fmt"

func main() {
var num, count int
count = 0
fmt.Print("Enter the number to find the prime number = ")
fmt.Scanln(#)

for i := 2; i < num/2; i++ {
if num%i == 0 {
count++
break
}
}

if count == 0 && num != 1 {
fmt.Println(num, " is a Prime number")
} else {
fmt.Println(num, " is not a Prime number")
}
}```
```

## OUTPUT

```Enter the number to find the prime number = 3
3  is a Prime number

Enter the number to find the prime number = 25
25  is not a Prime number```
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