Problems override operator << for output cout

ostream& String::operator<<(ostream& stream,const String& str){

#include <iostream>
#include <cstring>
using std::cout;
using std::cin;
using std::endl;
using std::ostream;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

class String{
	char *ch;
public:
	String();
	String operator=(char* ob);
	String operator+(String str);
	char * toString();
	friend ostream& operator<<(ostream& stream,const String& str);
};

String::String(){
}

String String::operator=(char* ob){
	ch=ob;
	return *this;
}

String String::operator+(String str){
	String temp;
	temp.ch=strcpy(ch,str.ch);
	return temp;
}
ostream& String::operator<<(ostream& stream,const String& str){
	stream<<str.ch;
	return stream;
}

char * String::toString(){
	return ch;
}

int main(int argc, char *argv[]) {
	String str1,str2,str3;
	str1="ehsan";
	str2="shahbakhty";
	cout<<str2;
	return 0;
}