main.c

#include <stdio.h>
#include <sys/time.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
    //arg
    unsigned int max = atoi(argv[1]);
   
    unsigned int count, i, div_count, divisor;

    //time var
    double timeStart, timeEnd, Texec;
    struct timeval tp;

    //start time
    gettimeofday(&tp, NULL);
    timeStart = (double) (tp.tv_sec) + (double) (tp.tv_usec) / 1e6;
    
    //iterate between min to max
    //optimize loop by going 100 to 1 instead of the inverse
    for(i = 1; i <= max; i++)
    {
        //check if current number has height divisors. Actually, check for 6 because a number will always has 1 and itself as divisors
        div_count = 0;
        divisor = 1;

        while(divisor <= i)
        {
            if (i % divisor == 0){
                div_count += 1; 
            }
            
            
            divisor += 1;    
        }
        
        if(div_count == 8)
        {
            count += 1;    
        }
    }
    
    //end timer
    gettimeofday(&tp, NULL);
    timeEnd = (double) (tp.tv_sec) + (double) (tp.tv_usec) / 1e6;
    Texec = timeEnd - timeStart;
    printf("\nExecution time : %f seconds", Texec);
    
    printf("\nCount : %d\n", count);
    
   
    return 0;    
}