Basic question and Answer question (C + +)

1. Brief description of the differences between sizeof and strlen

One of the most frequently examined topics. The main differences are as follows:

1) sizeof is an operator and strlen is a library function.

2) The parameters of sizeof can be either the type of the data or the variable, and the strlen can only be used as arguments with a string ending as ' \ '.

3) The compiler calculates the results of sizeof at compile time. The strlen function must not be evaluated at run time. And sizeof calculates that the data type accounts for the size of the memory, and Strlen calculates the actual length of the string.

4) The parameters of the sizeof array do not degenerate, passed to the strlen is reduced to a pointer.

Basic question and Answer question (C + +)