C++中string类型 任性！

/* C++中的新成份——string类型 */#include<iostream>#include<cstring>using namespace std;int main(){    char str1[50],str2[50],temp[50];    cout <<"please input strings:";    cin>>str1>>str2;    if(strcmp(str1,str2)>0)    {        strcpy(temp,str1);        strcpy(str1,str2);        strcpy(str2,temp);    }    cout<<"now,they are:";    cout<<str1<<","<<str2<<endl;}#include<iostream>#include<string>using namespace std;int main(){    string str1,str2,temp;    cout<<"please input strngs:";    cin>>str1>>str2;    if(str1>str2)    {        temp=str1;        str1=str2;        str2=temp;    }    cout<<"now,they are:";    cout<<str1<<","<<str2<<endl;}#include<iostream>#include<cstring>using namespace std;int main(){    char *str1,*str2,temp;//错误的！ 野指针     cout<<"please input strings:";    cin>>str1>>str2;    if(strcmp(str1,str2))    {        strcpy(temp,*str1);        strcpy(*str1,*str2);        strcpy(*str2,temp);    }    cout<<"now,they are:";    cout<<str1<<","<<str2<<endl;}