mirror of https://github.com/TheAlgorithms/C
Add Sieve of Eratosthenes
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdbool.h>
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void primes(bool * primeList, int len) {
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int i, j;
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// Initiallize the list
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for (i = 0; i < len; i++) {
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primeList[i] = true;
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}
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primeList[0] = false; // 0 is not prime
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primeList[1] = false; // 1 is not prime
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for (i = 0; i < len; i++) {
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if (primeList[i] == true) {
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for (j = i*i; j < len; j = j+i) {
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primeList[j] = false;
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}
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}
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}
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}
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int main(void) {
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int size, i;
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bool * list;
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// Ask for the largest value to check primeness
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printf("Maximum value: ");
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scanf("%d", &size);
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// Allocate list to act as prime mask
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list = malloc(sizeof(bool) * size);
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// Populate list
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primes(list, size);
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// Print prime numbers
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for (i = 0; i < size; i++) {
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if (list[i] == true) {
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printf("%d\n", i);
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}
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}
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return 0;
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}
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