在std中还有个ostringstream这么方便的格式化输出的工具

std::string generate(){    ostringstream osm;    osm << "xxxx " << 1111;        // 清空之前的内容    osm.str("");        // 浮点数转换限制    double tmp = 123.1234554351236234;    osm.precision(15);    osm.setf(std::ios::fixed); // 将浮点数的位数限定为小数点之后的位数    osm << tmp;    return osm.str();}

需要包含的头文件：

#include <sstream> 

ostringstream作用、主要接口：

Output string stream classios_base  ios  ostream  ostringstream ostringstream provides an interface to manipulate strings as if they were output streams.The objects of this class maintain internally a pointer to a stringbuf object that can be obtained/modified by calling member rdbuf. This streambuf-derived object controls a sequence of characters (string) that can be obtained/modified by calling member str.Public members(constructor) Construct an object and optionally initialize its content (constructor member) rdbuf Get/set the associated stringbuf object (public member function) str Get/set the associated string object (public member function) 

一个非常简单又快捷的格式化输出工具。