# 7. C PROGRAMMING LAB | Check Now

C PROGRAMMING LAB –07] Implement using functions to check whether the given number is prime and display appropriate messages

## Algorithm

• Step-1: Start
• Step-2: [Read the value of N ( positive integer )]-Read N
• Step-3: [Check whether the N is prime or not]-
• for i = 2 to m/2
• if m % i = 0 than goto step 4 otherwise goto step 5
• Step-4: Print the message of the number is not prime
• Step-5: Print the message of the number is prime number
• Step-6: stop

## Program -7 source code

```#include<stdio.h>
int isprime(int n);

int main()
{
int i,m1,m2;
printf("enter range\n");
scanf("%d%d",&m1,&m2);
printf("prime num from %d to %d are:\n",m1,m2);
for(i=m1;i<=m2;i++)
{
if(isprime(i))
printf("%d\n",i);
}
}

int isprime(int m)
{
int i;
for(i=2;i<=m/2;i++)
{
if(m%i==0)
{
return 0;
}
}
return 1;
}```

or

```#include<stdio.h>
int isprime(int);
int main()
{
int num;
printf("Enter value of num:\n");
scanf("%d",&num);
if (isprime(num))
printf("%d is a prime number",num);
else
Printf(“%d is not a prime number”,num)
}
int isprime(int x)
{
int i;
for(i=2;i<=x/2;i++)
if(x%i == 0)
return 0;
return 1;
}```

## C PROGRAMMING -Output

• Enter range
• 1
• 80
• prime num from 1 to 80 are :
• 1
• 2
• 3
• 5
• 7
• 11
• 13
• 17
• 19
• 23
• 29
• 31
• 37
• 41
• 43
• 47
• 53
• 59
• 61
• 67
• 71
• 73
• 79

OR

Enter the value of num: 3

3 is a prime number

## C PROGRAMMING -Viva Questions

1] What is a prime number?

2] Give examples for prime numbers?

3] What are keywords?

4] What are conditional statements?