Linux C CPU Benchmark

#include <iostream>
#include <stdio.h>
#include <sys/time.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <wait.h>

#define NUM_OF_CORES sysconf(_SC_NPROCESSORS_ONLN)
#define MAX_PRIME 150000

void do_primes(int coreNum)
{
    int i, num, primes = 0;
    struct timeval startP, endP;
    long run_timeP, secondsP, usecondsP;
    gettimeofday(&startP, NULL);

    for (num = 1; num <= MAX_PRIME; num++)
    {
        for (i = 2; (i <= num) && (num % i != 0); i++);

        if (i == num)
        {
            primes++;
        }
    }

    gettimeofday(&endP, NULL);
    secondsP  = endP.tv_sec - startP.tv_sec;
    usecondsP = endP.tv_usec - startP.tv_usec;
    run_timeP = ((secondsP) * 1000 + usecondsP / 1000.0) + 0.5;

    printf("\033[1;32m[ OK ]\033[0m Core #%d finished test...\n", coreNum);
    printf("\033[1m[INFO]\033[0m Core #%d finished in %ldms\n", coreNum, run_timeP);
}

int main(int argc, char ** argv)
{
    system("clear");
    printf("\033[1;32m[ OK ]\033[0m Initializing...\n");
    printf("\n============\033[1m[ System Info ]\033[0m==============\n");
    printf("\033[1m[INFO]\033[0m       CPU name: ");
    fflush(stdout);
    system("grep -i --color 'model name' /proc/cpuinfo | uniq | sed -e 's/model name//' | sed -e 's/: //' | sed -e 's/          //'| sed -e 's/ //' | sed -e 's/@.*//'");
    printf("\033[1m[INFO]\033[0m      CPU speed: ");
    fflush(stdout);
    system("grep -i --color 'model name' /proc/cpuinfo | uniq | sed -e 's/.*@ //'");
    printf("\033[1m[INFO]\033[0m # of CPU cores: %ld\n", NUM_OF_CORES);
    printf("\033[1m[INFO]\033[0m    Test number: %d\n", MAX_PRIME);
    printf("\n===========\033[1m[ Starting Test ]\033[0m=============\n");
    printf("\033[1;32m[ OK ]\033[0m Starting tests...\n");

    struct timeval start1, end1;
    long run_time, seconds, useconds;
    gettimeofday(&start1, NULL);

    unsigned long i;
    pid_t pids[NUM_OF_CORES];

    for (i = 0; i < NUM_OF_CORES; i++)
    {
        if (!(pids[i] = fork()))
        {
            do_primes(i);
            exit(0);
        }

        if (pids[i] < 0)
        {
            perror("Fork");
            exit(1);
        }
    }

    for (i = 0; i < NUM_OF_CORES; i++)
    {
        waitpid(pids[i], NULL, 0);
    }

    gettimeofday(&end1, NULL);

    printf("\033[1;32m[ OK ]\033[0m Test done, calculating results...\n");

    seconds  = end1.tv_sec - start1.tv_sec;
    useconds = end1.tv_usec - start1.tv_usec;
    run_time = ((seconds) * 1000 + useconds / 1000.0) + 0.5;

    printf("\n==============\033[1m[ Results ]\033[0m================\n");
    printf("\033[1m[INFO]\033[0m     Time taken: %ldms", run_time);

    printf("\n\n");
    return 0;
}