What does sizeof do in C++?

In C++, sizeof is an operator used to determine the size in bytes of a type or variable. It can be used for various purposes.

1. To determine the size of a data type, you can use sizeof which will return the number of bytes the data type occupies. For example, sizeof(int) will return 4, as in most systems, an int type occupies 4 bytes.
2. To obtain the size of a variable: you can use sizeof to determine how many bytes a variable occupies. For example, sizeof(variable) will return the number of bytes the variable occupies.
3. To obtain the size of an array, you can use sizeof to get the number of bytes occupied by the array. For example, sizeof(array) will return the total number of bytes occupied by the array.

The sizeof operator returns a value of type size_t, indicating the size in bytes.