C Programs For Prime Number (Definition,Example,Program) - Do Tech Blog

C Programs For Prime Number: In this article, we will know what is the prime number. and at the same time, we will know how to find the prime number in c as well as an example with explanation. We will perform this example in different ways.

## What is a prime number?

The prime number is the whole number. Which is greater than 1. Which is evenly dived from one or its own number. It is called a prime number.

Example: 2 is the prime number which is divided evenly from 1 or 2 itself.

Other example: 2,3,5,7,11, etc.

## Prime Number Algorithm in c

1. Start
2. The user will get an integer variable X inter
3. Will divide the variable with (X-1 to 2)
4. If X is divisible with any value (X-1 to 2) then not prime
5. else X is a prime number
6. Stop

We will perform the program of a prime number in c in the following way.

1. The prime number using Function
2. Prime number program in c using for loop
3.  Prime number program in c using while loop
4. Print Prime Numbers from 1 to n

## Prime Number Program  in C

### The prime number using the function

#include <stdio.h>

int prime_find (int);

main ()

{

int a, b;

printf ("Enter Integer Number to Find Prime or Not. \ n");

scanf ("% d", & a);

b = prime_find (a);

if (b == 1)

printf ("% d is prime. \ n", a);

else

printf ("% d is not prime. \ n", a);

return 0;

}

int prime_find (int x)

{

int y;

for (y = 2; y <= x - 1; y ++)

{

if (x% y == 0)

return 0;

}

return 1;

}

Input

Enter Integer Number to Find Prime or Not.5

Output

5 is prime

Prime number program in c using for loop

#include <stdio.h>

int main ()

{

int a, b, c = 0;

printf ("Enter Integer Number to Find Prime or Not. \ n");

scanf ("% d", & a);

for (b = 2; b <= a / 2; ++ b)

{

// check for non prime number

if (n% b == 0)

{

c = 1;

break;

}

}

if (c == 0)

printf ("% d is a prime number.", a);

else

printf ("% d is not a prime number.", a);

getch ();

}

Input

Enter Integer Number to Find Prime or Not.5

Output

5 is a prime number

### Prime number program in c using while loop

#include <stdio.h>

int main ()

{

int n, i, count = 0;

int a, b, c = 0;

printf ("Enter Integer Number to Find Prime or Not. \ n");

scanf ("% d", & a);

b = 2;

while (b <= a / 2)

{

// check for non prime number

if (a% b == 0)

{

c = 1;

break;

}

b ++;

}

if (c == 0)

printf ("% d is a prime number.", a);

else

printf ("% d is not a prime number.", a);

getch ();

}

Input

Enter Integer Number to Find Prime or Not.5

Output

5 is a prime number

### Print Prime Numbers from 1 to n

#include <stdio.h>

int main () {

int a, b, count, n;

printf ("Enter Rang For To Find Prime Number");

scanf ("% d", & n);

for (a = 1; a <= n; a ++) {

count = 0;

for (b = 2; b <= a / 2; b ++) {

if (a% b == 0) {

count ++;

break;

}

}

if (count == 0 && a! = 1)

printf ("% d", a);

}

return 0;

}

Input

Enter Rang For To Find Prime Number 5

Output

2 3 5