C++:: 将 ASCII 值转换为字符串
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C++:: Convert ASCII value to string in
提问by Kenneth Yang
I am trying to convert an int that represents the ASCII value of a character to a single-character string.
我正在尝试将表示字符的 ASCII 值的 int 转换为单字符字符串。
I tried the following, and it does not work: string s1=(char) 97;
我尝试了以下方法，但不起作用： string s1=(char) 97;
However, the conversion works only if I break the assignment apart like this:string s1;
s1=(char) 97;
但是，只有当我像这样将分配分开时，转换才有效：string s1;
s1=(char) 97;
I am confused by this and can anyone explain the difference?
我对此感到困惑，任何人都可以解释其中的区别吗？
Thanks in advance!
提前致谢！
回答by syam
I tried the following, and it does not work:
string s1=(char) 97;
我尝试了以下方法，但不起作用：
string s1=(char) 97;
That's because the std::stringconstructordoesn't have any overload that takes a single char. And also, copy is elided so the constructor is called directly, operator =()is never called (document yourself on copy elision).
那是因为std::string构造函数没有任何需要单个char. 而且，复制被省略，因此构造函数被直接调用，operator =()从不调用（在复制省略上记录自己）。
the conversion works only if I break the assignment apart like this:
string s1; s1=(char) 97;
只有当我像这样将分配分开时，转换才有效：
string s1; s1=(char) 97;
Now the copy is not elided any more, you are really calling std::string::operator =()which doeshave an overload accepting a single char.
现在副本不再被省略，您实际上正在调用std::string::operator =()它确实具有接受单个char.
