sizeof

求数组长度

char str1[11] = "Hello";
int size = sizeof(str1) / sizeof(char);
//打印11
cout << "str1.array.size=" << size << endl;

分配内存

short shortarray[10] = {};
  int intarray[10] = {};
  long longarray[10] = {};
  long long longlongarray[10] = {};

  // 20 字节
  cout << "shortarray.size" << sizeof(shortarray) << endl;
  // 40
  cout << "intarray.size" << sizeof(intarray) << endl;
  // 40
  cout << "longarray.size" << sizeof(longarray) << endl;
  // 80
  cout << "longlongarray.size" << sizeof(longlongarray) << endl;