c++的字符串反转

#include <iostream>

using namespace std;

namespace mydata {
    string str;
    void strShuRu();
    int strLength();
}

void mydata::strShuRu()
{
    getline(cin,str);
}

int mydata::strLength()
{
    int len=str.length();
    return len;
}

string strFanZhuan(string str,int len)
{
    string strr=str;
    int lens=len;
    char temp;
    int j=lens-1;
    for(int i=0;i<lens/2;i++)
    {
        temp=strr[i];
        strr[i]=strr[j];
        strr[j]=temp;
        j--;
    }
    return strr;
}

using namespace mydata;
int main()
{
    strShuRu();
    int len=strLength();
    cout << str.size() << endl;
    cout << len << endl;
    string fanStr=strFanZhuan(str,len);
    cout << fanStr <<endl;
    return 0;
}