字符串除去标点的小程序 vc++编译友4个错误 求高手指教
#include<iostream>
#include<string>
#include<cctype>
using namespace std;
int main ()
{
string s1,s2,ch=" ";
cout<<"enter a string"<<endl;
getline(cin,s1);
while(string::size_type i=0,i!=s1.size(),i++)
{
if(!ispunct(s1[i]))
{
ch[0]=s1[i];
s2+=ch;
}
}
cout<<s2<<endl;
return 0;
}