适用boost regex检测 输入字符为小数

#include <boost/regex.hpp>
#include <string>
#include <iostream>
#define REGEX_ISFLOAT        "[0-9]|[0-9]\.[0-9]"
#define REGEX_ISNUM        ""
#define REGEX_ISAL            ""

using namespace std;
using namespace boost;
boost::regex expression(REGEX_ISFLOAT);//设定正则规则
std::string str;

int main(int argc, _TCHAR* argv[])
{
    while(1)
    {
        cout<<"输入"<<endl;
        cin>>str;

    
        if( regex_match( str,expression)) //字符串匹配
        {
            cout<<"匹配成功"<<endl;
        }
        else
        {
            cout<<"匹配失败"<<endl;
        }
    }
    return 0;

}