When does [C + +] need "#include string.h"

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In C + +, the string header file is basically included in the iostream.
However, it is recommended to add #include<string.h> when using it (especially in the following cases)
1. Using string type
2. Use CIN, cout statement to input output string type variable (note, also need #include<sstream>)
3, when using memset (), strlen (), strcpy () and other functions.

When does [C + +] need "#include string.h"