How to allocate as much dynamic memory for a variable as needed?

Question

C++ / C#

char t[80];
cout << sizeof t << endl; // 80 байт, всё правильно
char *p = new char[80];
cout << sizeof *p << endl; // 1 байт. Почему?

When working with static memory, exactly 80 bytes are allocated, which is true, and when working with dynamic (heap) 1 byte is allocated. Why? What am I doing wrong?

Answer 1

In the first case, you get the length of a static array, sizeof works like sizeof(char)*StaticLength.
In the second case, you get the size of the first element pointed to by p. *p --> p[0] where sizeof(p[0] --> char) while *(p+1) --> p[1]
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