How do you write a c program to find prime numbers between 1 to 10000 using functions?

Answer 1

You need two utility functions. The first determines if a given number is prime or not. The second finds the next prime after a given number.

The following function can be used to determine if a given integer is prime:

bool is_prime (const unsigned num) {

if (num<2) return false;

if (0==(num%2)) return num==2;

unsigned max_factor = (unsigned) sqrt ((double) num) + 1;

unsigned factor;

for (factor=3; factor<max_factor; ++factor)

if (0==(num%factor)) return false;

return true;

}

The following function can be used to determine the next prime after the given integer:

unsigned next_prime (unsigned num) {

while (!is_prime (++num));

return num;

}

Now you can print a series of primes using the following:

int main (void) {

unsigned num=1;

while (num<10000) {

num = next_prime (num);

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

}

return 0;

}