vector<string> or vector<char *>?

Question

Question:

• What is the difference between:

  • vector<string> and vector<char *>?

• How would I pass a value of data type: string to a function, that specifically accepts:

  • const char *?

For instance:

 vector<string> args(argv, argv + argc);

 vector<string>::iterator i;

 void foo (const char *); //*i

• I understand using vector<char *>: I'll have to copy the data, as well as the pointer

Edit:

Thanks for input!

Answer 1

This really has nothing to do with vectors specifically.

A char* is a pointer, which may or may not point to valid string data.

A std::string is a string class, encapsulating all the required data that makes up a string, along with allocation and deallocation functionality.

If you store std::string's in a vector, or anywhere else, then everything will just work.

If you store char pointers, you have to do all the hard work of allocating and freeing memory, and ensuring the pointers only ever point to meaningful string data, and determine the length of the strings and so on.

And since char*'s are expected by a lot of C API's as well as part of the C++ standard library, the string class has the c_str() function which returns a char*.