C ++：char test [100]与数组 <char, 100> vs字符串

Question

If I have a string that I know will be of constant length, what should I use?

char test[100]
std::array<char, 100> test
std::string test

Thanks!

Answer 1

The answer is in the question:

If I have a string ...

If you have a string, use std::string . Unless you have very specific requirements that you have not mentioned.

Answer 2

In C++ a string should be declared as a string instance. But if you need it to be constant then declare it as a const string and initialize it properly.

char test[100] is not a string but a C-array of 100 chars (that can be used to build a C++ string if needed).

std::array<char,100> test is just a C++ array of hundred chars, nothing related to string.

Answer 3

Whether you know it will be constant length or not, it's pretty much always going to be recommended that you use std::string . Having the string be contained in an actual string object enables you to query the string for metainformation (length, for example) and integrate better with C++ functionality for handling strings. If ensuring that the string /cannot/ be more than 100 characters is super vital to you, you might find

std::array<char, 100>

to be valuable, but I can't think of any situations where you'd rather have that functionality than just using a string.

Answer 4

Unless you have a reason otherwise you should prefer a std::string . Not only does this say that the data is a string but you get all of the nice string functions as well.

You also get the benefit that if you decide to change the code and allow variable/larger sized strings then you don' need to change anything as std::string will scale