stringstream之int和string数据类型互换

需要包含的头文件是

#include <sstream>

1.string型转int型

stringstream sstream;
string str = "321";
int num = 0;
sstream << str;
sstream >> num;
cout<<num;

2.int转string

stringstream sstream;
int nn = 123;
sstream << nn;
cout << sstream.str();

3.stringstream的重复使用，当你连续的使用stringstream来做数据类型转换的时候，你会发现这样的问题

stringstream sstream;
string str = "321";
int num = 0;
sstream << str;
sstream >> num;
cout<<num;
int nn = 123;
sstream << nn;
cout << sstream.str();

和最初赋的值一样竟然，

其实stringstream在重新使用的时候需要清空，同时要把str()赋成空字符串。

stringstream sstream;
string str = "321";
int num = 0;
sstream << str;
sstream >> num;
cout<<num;
sstream.clear();
sstream.str("");
int nn = 123;
sstream << nn;
cout << sstream.str();

这样就对了