You need to specify the namespace for the string (which happens to be std). There are two options: include<string.h> int main() { std::string s1("hello world"); return 0; } or include<string.h> using namespace std; int main() { string s1("hello world"); return 0; } Chris ----- Original Message ----- From: "Wim Verleyen" <verleyen.wim@xxxxxxxxxx> To: <gcc-help@xxxxxxxxxxx> Sent: Friday, June 04, 2004 7:08 PM Subject: string class > Hello, > > I try to compile following C++ program on gcc/g++ version 3.3. > > include<string.h> > > int main() > { > string s1("hello world"); > > return 0; > } > > make gives me: > > - string undeclared (first use in this function).... > > plz help me... > > Wim > >