## prime numbers:

prime numbers are divisible by only 1 and that number itself. Eg.in this program, as per divisions, integer number 5 can be divided by 1 and integer number 5 which is nothing but original number so it is prime number. 2 is the only even prime number.

**prime number:**2,3,5,7,11,13,17,19,23,29,…

## logic:

Below program to find prime number takes user input and then if condition inside for loop checks whether number is divisible by smaller number than input number which is 1 or number itself.

```
#include<stdio.h>
#include<conio.h>
#include<math.h>
void printprimes();
int checkprimes(int num);
void main()
{
int i;
int flag;
printf("\n Prime numbers from 1 to 100:");
printprimes();
getch();
}
void printprimes()
{
int i,j;
for(i=2;i<=100;i++)
{
if(checkprimes(i));
printf("%d\t",i);
}
}
int checkprimes(int num)
{
int j;
for(j=2;j<=sqrt(num);j++)
{
if(num%j==0)
return 0;
}
return 1;
}
```

**Ouput:**

Similar programs:You might also like to see:

Program to find prime number using function

The prime numbers, provides an accurate calculation of P(N) by the method of Prime Number Distribution Series (PNDS), developed by the NSI team of mathematicians2.