Created
December 8, 2023 14:44
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A prime calculator to test the speed of a server
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| #include <stdio.h> | |
| #include <stdlib.h> | |
| #include <stdbool.h> | |
| #include <math.h> | |
| #include <time.h> | |
| /** | |
| * Defined as a default. You can pass any value as first parameter. | |
| */ | |
| #define LIMIT (200000) | |
| /* | |
| * This software is not useful to calculate the prime numbers | |
| * but really a good method to test the speed of a CPU. Note | |
| * the program should work on a single core and this could | |
| * modify the speed perception. | |
| * | |
| * How to use it? | |
| * cc primes.c && time ./a.out | |
| * | |
| * This will give you the CPU usage used by the software. It | |
| * is a very fast and very simple way to check the speed of | |
| * a VPS (like Amazon EC2 or any other provider). | |
| */ | |
| int isPrime(int input){ | |
| for(int i = 2; i < input - 1; i++){ | |
| if( input % i == 0) return false; | |
| } | |
| return true; | |
| } | |
| int main(int argc, char **argv) { | |
| time_t rawtime; | |
| int limit = LIMIT; | |
| if(argc > 1){ | |
| limit = atoi(argv[1]); | |
| } | |
| time_t previous = time(&rawtime); | |
| int last = 2; | |
| for (int i = 2; i < limit; i++) { | |
| if(isPrime(i)){ | |
| last = i; | |
| time(&rawtime); | |
| if(rawtime > previous){ | |
| printf("%d...\n", last); | |
| previous++; | |
| } | |
| } | |
| } | |
| printf("%d (done)\n", last); | |
| return 0; | |
| } |
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