This is weird. I created a vector just fine in one class but can't create it in another class. He's a representation of what I have:
main.h
#include <Windows.h>
#include <ShellAPI.h>
#include <vector>
#include <string>
#include <iostream>
#include "taco.h"
class MyClass
{
public:
int someint;
vector<int> myOrder;
};
taco.h
#include <vector>
class OtherClass
{
public:
vector<int> otherOrder;
};
And I get compile errors regarding the vector declaration in taco.h:
error C2143: syntax error : missing ';' before '<'
error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
error C2238: unexpected token(s) preceding ';'
What am I missing here? I can uncomment out that second vector declaration and it compiles fine.
Try:
std::vector<int> otherOrder;
vector is part of the std namespace. This means that whenever you use a vector in a header file, you should include the std:: prefix.
The reason that you can sometimes get away with forgetting it is that some included files may have using namespace std; in them, allowing you to leave off the prefix. However, you should avoid the using keyword in header files, for it will pollute the namespace of any files that include it.
For a more detailed explanation of the dangers of using namespace ..., see this thread.
Try std::vector<int>. You're supposed to use the namespace --- I'm assuming you have
using namespace std;
in the main.h someplace. There's a lot of talk on SO as to why using using is bad practice ; I'd recommend that you check it out.
All C++ standard library objects live in the std namespace. Try
class MyClass
{
public:
int someint;
std::vector<int> myOrder;
// ^^^^^
};
std::vector<int> ?
Related
class Space2D {
public:
vector<Agent> v;
bool star;
Space2D() {
bool star = false;
}
};
In visual studio this give me a error: missing type specifier - int assumed. I also get errors like syntax error: missing ';' before '<'.
std::vector<Agent> v; Solved this
Three possible problems with this code.
Possibly vector header is not included
Fix: #include <vector>
Possibly Agent class is not defined
Fix: include header, where Agent class is defined
Possibly you forgot to write using namespace std; as wrongly recommended by beginner books
Fix: instead of 'vector' on line 7 use std::vector, or do it wrong and write using namespace std;
Assuming from two error messages you posted and by guessing to which line they correspond to you forget to #include <vector> or you do not have imported std::vector to your namespace (using std::vector; or using namespace std).
I personally would not recommend using either of those usings for reasons and instead wrote std::vector.
First, Parameter.h:
#pragma once
#include <string>
class Parameter {
public:
Parameter();
~Parameter();
private:
string constValue;
string varName;
};
And Parameter.cpp:
#include "Parameter.h"
using namespace std;
Parameter::Parameter() {};
Parameter::~Parameter() {};
I've brought these two files down to the barest of bones to get the errors that seem to be popping up. At the two private declarations for strings, I get the two errors:
'constValue': unknown override specifier
missing type specifier - int assumed. Note: C++ does not support default-int
I've seen several questions with these errors, but each refers to circular or missing references. As I've stripped it down to what's absolutely required, I can see no circular references or references that are missing.
Any ideas?
As #Pete Becker points out in the comments, you need to qualify the name string as std::string:
private:
std::string constValue;
std::string varName;
The compiler just doesn't know what you're talking about, and it's the equivalent of just writing:
SomeGreatType myMagicalUniversalType
The compiler just doesn't know what type that is unless you've declared, hence the error
missing type specifier - int assumed
You should read up about why you should avoid using namespace std;.
With regards to your question in the comments:
In all the (working) classes I've written, I've never put in the std::, instead relying on the using namespace std; in the .cpp file. Why would this one be any different?
I can only infer that at some point before including "Parameter.h" that you had a using namespace std. E.g.:
// SomeType.h
#using namespace std
...
// Parameter.cpp
#include "SomeType.h"
#include "Parameter.h"
The compiler compiles things top-to-bottom, and including essentially just replaces the #include with the contents of that file
I'm trying to create a list of strings, following the example here. This below gives me syntax errors:
private: list<string> images;
The errors (all on the line where the above declaration is):
syntax error : missing ';' before '<'
missing type specifier - int assumed. Note: C++ does not support default-int
unexpected token(s) preceding ';'
It's in a class with only a single constructor besides it, and it compiles fine without it. What am I doing wrong?
Did you #include both <list> and <string>? Also, did you import the names list and string from namespace std by writing either
using namespace std;
or
using std::list; using std::string;
The error you're getting is consistent with the names not being accessible, so this is my best guess.
EDIT: Since this is in a header file, you should not be using either of the above constructs (thanks to wilhelmtell for pointing out that this is a header file!). Instead, you should fully-qualify the names as
private: std::list<std::string> images;
This way the compiler knows exactly where to look for list and string.
You need to qualify the list and string types with their namespace.
Either type std::list<std::string> or add using namespace std; after the #include <string> and #include <list> directives.
A simple working program:
#include <list>
#include <string>
using namespace std;
int main ( int, char ** )
{
list<string> strings;
strings.push_back("1st string");
}
I'm stuck! I have this very simple test code and I can't get it to compile! I have used the same code many times before but now it won't work!
I have this simple program
#include <vector>
#include <iostream>
#include "Rswap.h"
using namespace std;
int main(){
Rswap test();
cin.get();
return 0;}
And then the rswap.cpp...
#include <vector>
#include "Rswap.h"
Rswap::Rswap(){
V.push_back(9);
};
And then the rswap.h...
#ifndef Rswap_h
#define Rswap_h
class Rswap{
public:
vector<int>V;
Rswap();
};
#endif
I'm using Visual studio 2008. Is there something wrong that is obvious and I'm missing or what could it be! As I said I have used this snippet on several differnet occassions and I can't find any difference between this and those that work...
And i have tried both
vector < int > V; and vector <int> V; without any luck
I have stared at this blindly now for some while so I thought it's better to ask here!
rswap.h(7) : error C2143: syntax error : missing ';' before '<'
rswap.h(7) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
rswap.h(7) : error C2238: unexpected token(s) preceding ';'
At the point you #include "Rswap.h", you haven't declared using namespace std; yet, so the reference to vector in Rswap.h must be qualified with a namespace. Simply declare the vector with a namespace prefix.
class Rswap{
public:
std::vector<int>V;
Rswap();
};
Also, I suggest you #include <vector> from Rswap.h rather than relying on whoever uses Rswap.h to get the #include order right.
It should be
std::vector<int>V;
Ah, your using namespace std comes too late - it should be inserted BEFORE the rswap.h include. In any case, it's MUCH better to write std::vector instead.
You need to #include <vector> in rswap.h.
I'm trying to use list in c++, but I get the following error:
1>error C2143: syntax error : missing ';' before '<'
1>error C4430: missing type specifier int assumed. Note: C++ does not support default-int
1>error C2238: unexpected token(s) preceding ';'
With the following code:
#pragma once
#include "Includes.h"
class Polygon
{
public:
Polygon(void);
~Polygon(void);
void addVertice(hgeVector v);
void renderPolygon();
list<hgeVector> vertices;
};
Includes.h:
#ifndef INCLUDES
#define INCLUDES
#define safe_delete(d) if(d) { delete d; d=0; }
#define PI 3.14159
#include <stdio.h>
#include <list>
#include "\include\hge.h"
#include "\include\hgesprite.h"
#include "\include\hgefont.h"
#include "\include\hgeparticle.h"
#include "\include\hgerect.h"
#include "Car.h"
#include "HelperFunctions.h"
#include "config.h"
#include "Polygon.h"
using namespace std;
#endif
Just some general comments...
#define PI 3.14159
Please use M_PI in math.h, which is 3.141592653589793238462643.
#include "\include\hge.h"
#include "\include\hgesprite.h"
#include "\include\hgefont.h"
#include "\include\hgeparticle.h"
#include "\include\hgerect.h"
You should use forward slashes / here, and remove the leading \ before the include.
using namespace std;
Avoid this in header file. This will pollute all other users' global namespace. (Therefore, you should use std::list<hgeVector> vertices; in Polygon.h.)
The issue could be that the line list<hgeVector> vertices is being processed before using namespace std;, and so your compiler does not know what a list (without the std:: namespace qualifier) is. It's not clear to me in exactly what order these statements get processed since your two files include each other, and I don't know precisely how the non-standard #pragma once will handle this.
In any case, try qualifying list<hgeVector> as std::list<hgeVector>
Edit: Assuming #pragma once works just like include guards, then this problem will occur if some other file inlcudes includes.h, but not if some other file includes Polygon.h. If another file includes includes.h, what happens is that includes.h reaches #include <Polygon.h>, and the compiler starts processing Polygon.h. But then when #include <includes.h> is reached inside Polygon.h, nothing is effectively included since the INCLUDES guard is already defined, so you don't get the using namespace std; line before the compiler continues processing the rest of Polygons.h.
In general, try to avoid circular inclusion, and prefer forward-declarations.
I think you have circular "includes". You are including Includes.h in Polygon.h and including Polygon.h in Includes.h.
class template need a full type declaration to instantiate itself. Make sure you have included the header file where hgeVector is declared.
BTW, you have 'using namespace std‘ in your header - this is not a good practice. It will introduce unnecessary names to the current namespace.
Make sure hgeVector is defined.
You may have redefined list somewhere. Try using std::list.
Try something very simple like std::list<int>.
The answer (as Tyler McHenry pointed out) was circular inclusion!
After sorting out my includes I ended up with a compiled code like this (even without std:: infront of list:
#pragma once
#include <list>
#include "D:\Programmering\haffes\hge181\include\hge.h"
#include "D:\Programmering\haffes\hge181\include\hgevector.h"
using namespace std;
using namespace std;
class MyPolygon
{
public:
MyPolygon(void);
~MyPolygon(void);
void addVertice(hgeVector v);
void renderPolygon();
void setHotSpot(hgeVector v);
void translate(hgeVector v);
private:
list<hgeVector> vertices;
hgeVector hotSpot;
bool hotSpotUndef;
};
Thanks a bunch for all the fast and good answers!