atomic

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <omp.h>
int main()
{
    //starting time for calculating run time
    double start = omp_get_wtime( );
    //enum for purposes of declaring array size with variable
    enum SIZE {SIZE = 26};

    //array to hold number of occurences of each letter in alphabet
    //with index 0 representing A,..., index 25 = Z
    int s_res[SIZE] = {};

    //number of threads requested
    const int NUMB = 10;

    //char string for identifying chars from txt
    char * alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    //requessting that num threads is num of books
    omp_set_num_threads(NUMB);

    //omp parralel and for, using static, 1 because best time results for me
    #pragma omp parallel for schedule(static,1)
       for(int i=0;i<NUMB;i++)
       {
            //adding ID to char '0' will result in char '0' - '9' depending on ID
            char filename[] = {'0' + i,'.','t','x','t'};

            FILE *fptr;
            fptr=fopen(filename,"r");
            char ch;
            //loop through txt file char at a time
            while((ch=toupper((fgetc(fptr))))!=EOF)
            {
                //pointer to memory address of ch in alpha
                const char *ptr = strchr(alpha, ch);
                if(ptr!=NULL)
                {
                    //calculate correct index
                    int index = ptr - alpha;
                    #pragma omp atomic
                    //use index to increment array
                    s_res[index]++;
                }

            }
        }

    //ending time for calculating run time
    double end = omp_get_wtime( );

    printf("\nCompleted in %f seconds", end-start);
    printf("\nThe letter frequencies are:\n");
    //print results
    for (int i =0; i < 26; i++)
    {
        printf("%c's: %d\n", alpha[i], s_res[i] );
    }

}