mirror of https://github.com/TheAlgorithms/C
43 lines
937 B
C
43 lines
937 B
C
/**
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* \file
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* \brief [Problem 10](https://projecteuler.net/problem=10) solution
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* \author [Krishna Vedala](https://github.com/kvedala)
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*/
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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/** Function to check if a number is prime */
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char is_prime(unsigned long n)
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{
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for (unsigned long i = 2; i < sqrtl(n) + 1; i++)
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if (n % i == 0)
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return 0;
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return 1;
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}
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/** Computes sum of prime numbers less than N */
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unsigned long long sum_of_primes(unsigned long N)
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{
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unsigned long long sum = 2;
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for (long i = 3; i < N; i += 2) /* skip even numbers */
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if (is_prime(i))
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sum += i;
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return sum;
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}
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/** Main function */
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int main(int argc, char *argv[])
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{
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unsigned long n = 100;
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if (argc == 2) /* if command line argument is provided */
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n = atol(argv[1]); /* use that as the upper limit */
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printf("%ld: %llu\n", n, sum_of_primes(n));
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return 0;
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} |