Return int value to another funciton

Question

I am a complete beginner in C and I'm sorry in advance for a trivial question. Q: I would like to return the value of random_num variable that is calculated in number_generator function to the main function:

int main() //didn't paste headers and prototype 
{
   int random_num; // <= to here
   number_generator(random_num);
   printf("random number: %d", random_num);

   return 0;
}

int number_generator(int random_num)
{
   srand(time (0));
   random_num = (rand() % 100) + 0; // <= return value from here
} 

Currently, the terminal output of printf is 0 while it should be in a range from 0 to 100.

Answer 1

Do it the following way

int number_generator(void )

int main() //didn't paste headers and prototype 
{
   int random_num = number_generator(); // <= to here
   printf("random number: %d", random_num);

   return 0;
}

int number_generator(void )
{
   srand(time (0));
   return (rand() % 100) + 0; // <= return value from here
}

Another approach is the following

void number_generator(int *random_num);

int main() //didn't paste headers and prototype 
{
   int random_num; // <= to here
   number_generator( &random_num);
   printf("random number: %d", random_num);

   return 0;
}

void number_generator(int *random_num)
{
   srand(time (0));
   *random_num = (rand() % 100) + 0; // <= return value from here
} 

Pay attention to that adding 0 in this expression

(rand() % 100) + 0

does not make a sense. It is equivalent to

(rand() % 100)