I can't get my following c++ program compiled in Visual Studio 2010. I already have a working build of the same code so I know the code is correct. But I have no idea with what or how it was compiled.
So I would appreciate if someone could just copy the code and try to compile it in VS 2010.
Code:
http://codepad.org/4VtrVBdK
new:
Ok, I did editing according to the comments below. Now the only problems that seem to have remained are related to calls to the overloaded functions. So how to go about it?
so I know the code is correct
What you "know" is false. The code is wrong in many ways. Here is but one example:
for(unsigned int i=0;i<GPNO;i++) //SORTING ACCORDING TO FITNESS
for(unsigned int j=i+1;j<GPNO;j++)
if((gp[i]->fitness)>(gp[j]->fitness))
{
gp[i]->mycopy(tmp);
gp[j]->mycopy(gp[i]);
tmp->mycopy(gp[j]);
}
for(i=1;i<=no;i++)
{
gp[i]->mycopy(gp[GPNO-i]);
}
In the second for loop, i is undeclared. I suspect the original compiler was VC6, which allowed this.
Another problem is the way you're calling pow. You call it with macros (which are patently evil for this purpose), for instance:
pf[i].frq+=(unsigned int)pow(2,2*PF-1);
And the compiler doesn't know which version of pow you had in mind. Case in point for macros being evil for this purpose. Do this:
pf[i].frq+=(unsigned int)pow(2.0,2*PF-1);
Or better yet, get rid of the macros.
Another example of your code being wrong:
#include "stdlib.h"
#include "conio.h"
#include "math.h"
None of these includes are part of the Standard. If you can get them to compile, its only because your compiler was anticipating your mistake. But it's still a mistake.
Looks like you're missing using namespace std;
Related
I am learning C++ and was writing a simple program when I noticed that declaring a stack caused cout to not output to the terminal. Here is my program:
#include <iostream>
#include <stack>
int main ()
{
std::stack<int> myStack;
std::cout<<"Hello World!"<<std::endl;
return 0;
}
This problem only occurs in the Visual Studio Code editor. If I use an online C++ compiler, there are no issues and I see "Hello World!" as output. If I remove the declaration of the stack, the output is also normal, even in VS Code. However, when the declaration is present, I see no output when I compile and run my code in VS Code. I have no idea why this would be the case, and other STL containers (I've tested vector, array, and set) do not cause a similar issue, although the problem still occurs when queue is used.
Any help resolving this issue, or any insight as to why it occurs in the first place, would be greatly appreciated.
p.s. This is my first time asking a question, so I apologize if it is poorly written.
First of all, It's been 3 months since I started coding, so I might not know what I'm saying.
Feel free to correct me.
I have a question about using some API that is developed in C++11.
I am restricted to use only Visual Studio 2019.
The problem happens whenever I use std::string type data.
Because I'm using the API that is not opened I can only assume what the problem is.
When I declare a variable like this.
std::string* strCopy = new std::string(strOriginal);
It works, but when I code like this.
std::string strCopy = strOriginal;
or like this.
std::string strCopy(strOriginal);
Visual Studio don't even print the error log and just stop.
Some might say, "Then why don't you use the one that works", but the real problem is when I use std::vector, because while using vector I can't declare the std::string type data inside by using 'new' expression.
I was thinking if there is a way that I can build the code for only std::string type data with C++11 by using DLL or by defining something.
If anyone know how to solve this kind of problem or have dealt with similar problem please give me some advice.
I'm not sure what you mean by "the API that is not opened".
This code works fine for me:
#include <string>
#include <iostream>
int main () {
std::string original = "ABCDEF";
std::string strCopy = original;
std::cout << strCopy << std::endl;
}
and when I run it, it prints "ABCDEF".
What happens when you compile that program?
Recently I'm working on my toy final c++ project, which will read content from a file at the begining and then process it.
Here's the simplified code.
#include <iostream>
#include <fstream>
//using namespace std;
struct command{
int a;
};
command read[1];
int main() {
std::ifstream fin;
fin.open("123.txt");
if (!fin){
std::cout << "failed" << std::endl;
return 0;
}
char c;
fin >> c;
std::cout << c;
return 0;
}
It works fine with Visual Studio 2019. However, when I'm trying to use devc++ 5.11 TDM-GCC 4.9.2, a strange bug happens. I get a segmentation fault on line fin>>c;, with return code 3221225477.
With great effort, the easiest way to make this code works is changing the identifier read to names like reading or whatever. Besides, moving the line command read[1]; into main function also helps.
My questions are:
Is it a behavior related to the compiler? MSVC is fine but GCC 4.9.2 is a little bit old or ...?
Does the identifier read conflict with something in my code? Why does it not a compile error but a segmentation fault?
Why does moving the declaration of read into main function help?
Update:Thanks for tips and I removed using namespace std. I think it has something to do with ifstream, because just std::cout<<"hello world"; works.
-Wall -Wextra provides no warnings.
GCC compiler is stricter than other compiler.
According to tadman's describe, we can guess there's read symbol in namespace std.
So you put it out of main,it's a conflict, you put in the main, it become a local symbol.
There is very likely a collision happening between your read and another in the global namespace. Not all compilers handle this situation the same way, but you can always avoid it if you are careful.
Visual Studio's Intellisense (or whatever alternative you prefer) can help you identify what symbol your read is colliding with. To do that, scope or comment out your code, then start typing "read". If there's another read in your scope, you'll likely see it and be able to get information about it.
This is one of the reasons I don't like using namespace std;. It pollutes your global namespace with a bunch of stuff and increases your chance of collision with a standard library identifier.
So I've been googling for a decent while, a search here turned up nothing so sure hope this isn't a duplicate
I was having some problems with assigning values to strings in a map but found a much more interesting problem, in that I can literally copy paste the example found on C++ Reference for map::map and it still comes up with the same error in the intellisense error report thing in Visual Studio. Found below:
#include <map>
#include <iostream>
std::map<char,int> first;
first['a']=10;
first['b']=30;
first['c']=50;
first['d']=70;
This was in a header file loaded by the main .cpp so it's not in a function, I also copy pasted fncomp and classcomp on the offchance that it was an inbuilt function that got overridden (I was definitely out of ideas by this point) and unsurprisingly that wasn't it
Is my version of Visual Studio broken or something? I can't see what I could have possibly missed.
That error message makes no sense whatsoever, but that's probably only because you're confusing the heck out of your IDE by writing these expression statements in random empty space.
Assignments must go in a function.
Only declarations can live at namespace scope.
This works fine:
std::vector<int> v;
v.push_back(123);
but this throws a std::length_error:
std::vector<uint32_t> v;// or vector<unsigned __int32>
v.push_back(123);
It seems to be triggered by resizing, because
std::vector<uint32_t> v;
v.reserve(2);
triggers a debug assertion "iterator not dereferencable".
This occurs on Visual Studio 2008, but the same code works fine on Mac and Linux. Can anyone suggest a way to narrow down the search for an explanation?
UPDATE:
The rat's nest of static and dynamically linked dependencies in this project made it too time-consuming to find the offending library. I gave up and rebuilt every dependency from source. I lost two days of my life and still don't know exactly where the problem was, but the app runs! Thanks for your help.
This
#include <iostream>
#include <vector>
int main()
{
std::vector<unsigned __int32> v;
v.reserve(2);
std::cout << v.capacity() << '\n';
return 0;
}
runs without any hiccups for me in VS 2008. It prints 2.
What does this do for you? If it works, too, then my first few guesses are:
You invoked undefined behavior somewhere before. By the time execution gets to the code you showed, all bets are off.
This is across DLL boundaries and you linked together DLLs/EXE built with different settings.
The way to find out about this is to distill it down to the smallest possible test case exhibiting the behavior. (That shouldn't contain more than 50LoC, ideally, it's 10.) If you don't find the problem while doing so, append the example to your question.
Since the sample code is working, your sample must be wrong :-)
Try to get closer to the problem by making your sample more like the real code in small steps. At some point it should stop working and then you can identify the culprit.
Can you check if your implementation has two or more typedefs of uint32_t? Especially under different namespaces? (I know the chances are pretty slim, but it might be worth it - in the quest for platform compatibility, different libraries try to map a specific memory size to a type, and one of them might have slipped up).
VC++ 2008 does not provide an ISO C99 header, so you must have provided the definion somehow; perhaps the definition is flawed.