How to fix cyclic dependencies between two header files

Cyclicdeps.cxx

/**        DO AS YOU PLEASE PUBLIC LICENSE 
 *         Modified from the WTFPL, 2016
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 * Copyright (C) 2016 GNY-001F2
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/* So you have two header files, foo.h and bar.h. In foo.h you created a class called foo_t,
 * and in bar.h you created a class called bar_t.
 * Unfortunately, your solution also required that you have pointers to objects of foo_t in
 * bar_t and of bar_t in foo_t.
 * You can't #include<[foo.h|bar.h]> in [bar.h|foo.h] because that would be a cyclic
 * dependency. The compiler cannot resolve it due to missing symbols - it expects
 * to know about foo_t when it compiles bar_t and about bar_t when it compiles foo_t.
 * So instead, you can use a forward declaration of the class, and if the class is in a
 * namespace, you need to wrap your forward declaration around it. See below for an example:
 */

/* in your production code, always have include guards for your header files! */

//foo.h
namespace bar {
typedef struct bar_t bar_t;
}
namespace foo {
typedef struct foo_t {
    int fooint;
    std::weak_ptr<bar::bar_t> barptr;
} foo_t;
}
 
//bar.h
namespace foo {
typedef struct foo_t foo_t;
}
namespace bar {
typedef struct bar_t {
    char** barchar;
    std::weak_ptr<foo::foo_t> fooptr;
} bar_t;
}
 
//impl.cpp
//the compiler will not create conflicts
#include "foo.h"
#include "bar.h"
int main() {
  std::cout<<"This program compiled without errors."<<std::endl;
}