如何将字符串值分配给 C++ 中的字符串变量

Question

Shouldn't this work?

string s;
s = "some string";

Answer 1

Shouldn't this work?

 string s; s = "some string";

Well, actually it's spelled std::string , but if you have a using namespace std; ( absolutely evil ) or using std::string; (somewhat less evil) before that, it should work - provided that you also have a #include <string> at the top of your file.

Note, however, that it is wasteful to first initialize s to be an empty string, just to replace that value in the very next statement. (And if efficiency wasn't your concern, why would you program in C++?) Better would be to initialize s to the right value immediately:

std::string s = "some string" 

or

std::string s("some string");

Answer 2

Yes!

It's default constructing a string, then assigning it from a const char* .

(Why did you post this question?... did you at least try it?)

Answer 3

使用头文件 string.h 或 bits/stdc++.h 然后尝试 s.assign("some string");