C Program to Print Prime Numbers in a Given Range – Trial Division and Sieve

Posted on February 15, 2012June 23, 2026 by Sandeepa Nadahalli

This C program generates and prints all prime numbers in a given range and reports the total count. It uses an efficient is_prime() function with a √n bound, plus a Sieve of Eratosthenes for cases where you need all primes up to a large limit. Trial Division — Check Each Number in the Range For …

Prime Number Program in C – Check if a Number is Prime

Posted on September 30, 2011June 23, 2026 by Sandeepa Nadahalli

A prime number program in C checks whether a given integer is prime — divisible only by 1 and itself. Numbers like 2, 3, 5, 7, 11, and 13 are prime; 4, 6, 9, and 12 are not. This page covers two approaches: a basic trial division and an optimized version that skips even numbers, …