:读取a.txt中文本，统计文本中字母数量。

budui

供参考：

void solve()
{
   FILE *fp;
   char ch;
   int  cnt=0;
   fp = fopen("a.txt","r");
   if(fp == NULL){
      printf("cann't open the file!\n");
      return;
   }
   while (1){
       ch = fgetc(fp);
       if (ch == EOF) break;
       if ((ch >= 'A' && ch <= 'Z')||(ch >= 'a' && ch <= 'z')) cnt++;
   }
   fclose(fp);
   printf("Letters count:%d\n",cnt);
}