I have coded the following:
STDMETHODIMP CWrapper::openPort(LONG* m_OpenPortResult)
{
std::string str;
//const char * c = str.c_str();
// Open("test".c_str())
return S_OK;
}
The compiler tells me "There is no such member "string" in the namespace std".
My includes look like this:
#include "stdafx.h"
#include "Wrapper.h"
#include <string.h>
using namespace std;
Did I do anything wrong so far?
You need to add the following:
#include <string>
Related
I would like to implement a hash table example.
So for this aim, I have created one header, one hash.cpp and main.cpp files.
in my hash.cpp , I tried to run a dummy hash function which takes key value and turns into an index value. however, it throws an error(reference to 'hash' is ambiguous) whenever I try to create an object according to that hash class.
this is my main.cpp:
#include "hash.h"
#include <iostream>
#include <cstdlib>
#include <string>
#include <stdio.h>
using namespace std;
int main(int argc, const char * argv[]) {
hash hash_object;
int index;
index=hash_object.hash("patrickkluivert");
cout<<"index="<<index<<endl;
return 0;
}
this is my hash.cpp:
#include "hash.h"
#include <iostream>
#include <cstdlib>
#include <string>
#include <stdio.h>
using namespace std;
int hash(string key){
int hash=0;
int index;
index=key.length();
return index;
}
this is my hash.h
#include <stdio.h>
#include <iostream>
#include <cstdlib>
#include <string>
using namespace std;
#ifndef __hashtable__hash__
#define __hashtable__hash__
class hash
{
public:
int Hash(string key);
};
#endif /* defined(__hashtable__hash__) */
Your hash class symbol is clashing with std::hash
A quick fix could be using a global namespace qualifier
int main(int argc, const char * argv[]) {
::hash hash_object;
but a better and recommended one would be to stop polluting your global namespace with
using namespace std;
and just using std::cout or std::endl when you need them.
You could also create your own namespace in case you're writing a library.
Besides, you have some capital letter typos here:
index = hash_object.hash("patrickkluivert");
^ I suppose you're referring to the Hash() function here
and here
int Hash(std::string key) {
^ this needs to be capital as well
int hash = 0;
in case you want to match your declaration and avoid cast/linking errors.
Your hash class is conflicting with std::hash. Stop using using namespace std; right now. If you want to make print statements shorter, try using std::cout; using std::endl;
How I can sent string variable into function in other file?
main.cpp:
#include <iostream>
#include <conio.h>
#include <string>
#include "headers.hpp"
using namespace std;
int main()
{
string a;
cout<<"Type:"<<endl;
cin>>a;
other(a);
getch();
return( 0 );
}
headers.hpp:
#ifndef HEADERS_HPP
#define HEADERS_HPP
void other(string a);
#endif
function.cpp:
#include "headers.hpp"
#include <iostream>
#include <math.h>
using namespace std;
void other(string a){
cout<<a;}
I don't know why it doesn't work. Do you know solution?
If you are saying it does not compile, you have to move the #include <string> from main.cpp into headers.hpp
I am getting a bunch of errors saying "Undefined reference to ...", and cant understand why. I have read other questions with the error "Undefined reference to ...", but the answers doesent work for me. Here is part of my code:
main:
#include <iostream>
#include <armadillo>
#include <string>
#include <DombsMain.h>
using namespace std;
using namespace arma;
int main(){
cout << "Armadillo version: " << arma_version::as_string() << endl;
dombsmain::initilize("test");
return 0;
}
dombsmain.h:
#ifndef DOMBSMAIN_H_INCLUDED
#define DOMBSMAIN_H_INCLUDED
#include <string>
#include <vector>
#include "Body.h"
#include "Constraint.h"
#include <Solver.h>
namespace dombsmain {
extern void initilize(std::string fileName);
extern std::string inputfileName;
...blabla
}
#endif // DOMBSMAIN_H_INCLUDED
dombsmain.cpp:
#include <DombsMain.h>
#include <BallJoint.h>
#include <dombs.h>
#indlude blabla
using namespace std;
using namespace arma;
namespace dombsmain{
void initilize(string infileName){
inputfileName = infileName;
..blabla
I think the error has something to do with namespace dombsmain. DombsMain.h is included both in main and in dombsmain.cpp, but it still says that the variables and functions in the namespace in undefined. I think it might be some conflict with including DombsMain.h int both main and dombsmain.cpp. I tried deleting the #include <DombsMain.h> in main.cpp, but then I couldent call dombsmain::initilize("test");
You just forgot to define std::string inputfileName. For example you can do it in dobsmain.cpp:
namespace dombsmain{
void initilize(string infileName){
inputfileName = infileName;
}
std::string inputfileName = "";
}
I had a little problem with my code. I am trying to create a simple script with a simple header, but things aren't quite working out. I get the following error: Invalid use of non-static data member 'name'. Would really appreciate some help with this problem, I am still a beginner to C++. Thank you in advance!
//header file
#ifndef Game_main_h
#define Game_main_h
#include <iostream>
#include <string>
using namespace std;
class main
{
public:
void resetInput();
string name;
};
#endif
//executional file
#include "main.h"
#include <iostream>
#include <string>
#include <iomanip>
#include <locale>
#include <sstream>
using namespace std;
int main(int argc, const char * argv[])
{
int nr;
string agree;
cout << "Enter your name.\n";
std::getline(cin, main::name);
return 0;
}
You need to create an instance of class main to access it! E.g. say
main x;
std::getline(cin, x.name);
Besides that it's a not so good idea to name a class main.
I'm at a loss - i'm just getting into C++ and for some reason this is not working out for me. So i'm using Netbeans, and i've got the following main file:
#include <cstdlib>
#include "functions.h"
using namespace std;
int main(int argc, char** argv) {
f("help");
return 0;
}
Functions.h file:
#include <string>
#ifndef FUNCTIONS_H
#define FUNCTIONS_H
void f( string a );
#endif
and Functions.cpp file:
#include "functions.h"
void f( string a ) {
return;
}
So, long story short, it doesn't compile. It says it can't understand the string variable? I don't get it, i tried moving the include for string all over the place but nowhere seems to help. What do i do?
If you are attempting to use std::string, you have to #include <string> in your functions header, and call it std::string,since it is in the std namespace.
#ifndef FUNCTIONS_H
#define FUNCTIONS_H
#include <string>
void f( std::string a );
#endif
See this related post and also why is 'using namespace std' considered bad practice in C++?
You need to include string header file in Functions.h, also tell compiler that string is from std namespace.
#ifndef FUNCTIONS_H
#define FUNCTIONS_H
#include <string>
void f( std::string a );
#endif
Functions.cpp file:
#include "functions.h"
void f( std::string a ) {
return;
}
Better practice is to pass string by const reference
void f(const std::string& a ) {
return;
}
See Why is 'using namespace std;' considered a bad practice in C++?
Include the standard header: <string>
#include <string>