本文介绍了std::string 格式,如 sprintf的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我必须用 std::string
格式化 std::string
="http://en.cppreference.com/w/cpp/io/c/fprintf">sprintf
并将其发送到文件流中.我该怎么做?
I have to format std::string
with sprintf
and send it into file stream. How can I do this?
推荐答案
你不能直接这样做,因为你没有对底层缓冲区的写访问权限(直到 C++11;参见 Dietrich Epp 的 评论).您必须首先在 c 字符串中执行此操作,然后将其复制到 std::string 中:
You can't do it directly, because you don't have write access to the underlying buffer (until C++11; see Dietrich Epp's comment). You'll have to do it first in a c-string, then copy it into a std::string:
char buff[100];
snprintf(buff, sizeof(buff), "%s", "Hello");
std::string buffAsStdStr = buff;
但我不知道你为什么不只使用字符串流?我假设您有特定的理由不只是这样做:
But I'm not sure why you wouldn't just use a string stream? I'm assuming you have specific reasons to not just do this:
std::ostringstream stringStream;
stringStream << "Hello";
std::string copyOfStr = stringStream.str();
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