MinGW G++ 未编译

Question

I'm trying to compile a simple "hello world" C++ program but when I use the g++ command I get the error "undefined reference to `WinMain@16" this happens when I compile in vscode or in terminal, whats happening? code:

#include <iostream>
#include <vector>
#include <string>

using namespace std;

int main()
{
vector<string> msg {"Hello World"};

for (const string& word : msg)
{
    cout << word << " ";
}
cout << endl;
}

Answer 1

Your error is not a compiler, but a linker error. That means it still compiles fine but fails to link.

A header file gets included (if it can be found in the include path the compiler uses to find headers), so this works fine.

But for linking two (object-)files together it has to know which files should be linked. And how should it decide which files to use?

That's the cause to create projects in it (and other IDE's) or to create makefiles.

If you turn on full command line-logging in "Settings -> Compiler and debugger... -> Global compiler settings -> [the_compiler_you_use] -> Other settings (rightmost tab) -> Compiler loggin" you can see which commands are sent to the compiler/linker and where the difference is between a single file and a project with multiple files.

By the way: your book/tutorial should explain the steps needed to compile and link files, what happens if headers are included and how to use prebuild libraries/dlls.