c++ - 在 C++ 中获取没有 if-else 的字符串变量

Question

是否可以使用字符串获取变量的值，以尽量减少使用大型 if-else 语句。例如:

string a = "hello world";
string b = "foo";

string input;

cout << "a or b";
cin >> input;

//is something like the next line possible?
cout << "your answer is equal to " << string_to_variable(input) << endl;

如果用户输入“a”，这应该输出“hello world”，如果用户输入“b”，则输出“foo”。

谢谢。

Answer 1

Is it possible to obtain the value of a variable using a string to minimize the use of large if-else statements.

您可以使用 std:map<std::string, std::string>使编程更容易，但在此之下，它仍然使用大量比较和 if-else类型检查。

std::map<std::string, std::string>> mymap = {{"a", "hello world"}, {"b", "foo"}};

std::string input;

cout << "a or b";
cin >> input;

//is something like the next line possible?
cout << "your answer is equal to " << maymap[input] << endl;

如果你想让你的代码更精确，你可以使用:

auto it = mymap.find(input);
if ( it == mymap.end() )
{
   cout << "There is no answer corresponding to " << input << endl;
}
else
{
   cout << "your answer is equal to " << it->second << endl;
}

代替

cout << "your answer is equal to " << maymap[input] << endl;