[count num of character '' in string] use recursive finishe

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAX 100
void split(char s[], char s1[], char s2[])
{
        int l, m;
        int i,j;
        l = strlen(s);
        m = l/2;
        for (i = 0; i < m; ++i)
        {
                s1[i] = s[i];
                //s2[i] = s[l - m + i]; // can't use to split s2
        }
        s1[i] = '\0';
        for (i = m; i < l; ++i)
        {
                s2[i-m] = s[i];
        }
        s2[i-m] = '\0';
}
int numofA(char s[])
{
        int count;
        count = 0;
        for (int i = 0; i < strlen(s); ++i)
        {
                if(s[i] == 'A')
                        count++;
        }
        return count;
}
int countnumofAinstr(char s[],int n)
{
        int result;
        char s1[MAX], s2[MAX];
        if(strlen(s) == 1)
        {
            puts(s);
            if(s[0]=='A')
                return 1;
            else
                return 0;
        }
        split(s,s1,s2);
        //result = countnumofAinstr(s1) + countnumofAinstr(s1);
        return countnumofAinstr(s1,n/2) + countnumofAinstr(s2,n/2);
}
int main(int argc, char const *argv[])
{
        char s[] = "AAAAAAAAAAAAAAAAAAAAEAAAAAAAAAAEEEEEAAAAAAAAAA";
        int l;
        l =strlen(s);
        printf("%d\n", countnumofAinstr(s,l));
        system("pause");
        return 0;
}