prime numbers using return 0 as condition

ok i know there is a million example programs to find out if entered number is prime. I want to do it a specific way and understand it at the same time. i am a complete novice as i am just learning some basic C in my unix class.
ok that all said herei s how i want to write the code

int num,div=2;
scanf("%d",&num)
/* from here i want to run a loop that divides num by div until either return 0 is given meaning an integer( this is where what i want to do differs - i'm checking for an integer output and if an integer is returned printf("not prime") otherwise loop until div=num(although don't include div=num obviously) and if it completes all loops e.g returns 1 all the way through then printf("prime").
*/
/*i really don't know C enough to understand the syntax of where to put the div++ and how to write - if return 0 printf("not prime") else div++ - then if it completes all loops for div=2;div<!=num printf("prime") -
i hope this makes sense any input at this point is a plus.
thanx in advanced
*/