i'm having problems with writing a program using arrays. i have to get the program to print out all the prime numbers up to 500. I'm using if/else statements and for loops but all i'm getting in return is 0 when i run the program. What am i doing wrong.

Here's a sample of my work:
for(digit=2; digit<=500; digit++)
{
if(digit*2 != digit)
PrimeNum[digit]
}