c++ - 在 C++ 中替换字符串中的字符

Question

在我的应用程序中，我将从数据库中检索错误消息字符串。我想将数字替换为错误消息。错误消息将是一个 C 风格的字符串，如：

Message %d does not exist

或者

Error reading from bus %d

理想情况下，我希望能够使用此语句执行 C 样式 printf，并替换我自己的数字。我知道我可以手动完成，但是有没有更简单的方法可以像常规字符串一样使用它打印？

Answer 1

除了简单的字符串连接或<<与数字和消息一起使用。

我能想到boost::format

int message_no=5;
std::cout << boost::format("Message %d doesn't exist") % message_no ;

Answer 2

The C++ way is to use std::stringstream:

std::stringstream str;
str << "Message " << messageName << " doesn't exist";

std::string out = str.str();

There is also very nice header-only boost string algorithms library:

std::string message = "Message %s doesn't exist";
boost::replace_first( str, "%s", "MyMessage" );

// message == "Message MyMessage doesn't exist"

and boost::format, which acts like printf, but is entirely type-safe and supports all user-defined types:

std::string out = format( "Message %1 doesn't exist" ) % "MyMessage";