Joel Coding Problem count_run_len

#include <stdio.h>
#include <assert.h>
int count_run_len(const char* str) {
  int ans = 0;

  int cnt = 0;
  char ch = 0x0;
  for (int i = 0; str[i] != 0x0; ++i) {
    if (str[i] == ch) {
      cnt++;
      if (cnt > ans) {
        ans = cnt;
      }
    } else {
      ch = str[i];
      cnt = 1;
    }
  }

  return ans;
}

int main(){
  assert(count_run_len("aaaaaaaabccccdbbbbb") == 8);
  assert(count_run_len("baaaaab") == 5);
  return 0;
}