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path: root/examples/hello_world/main.cpp
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#include <fruit/fruit.h>
#include <iostream>

using fruit::Component;
using fruit::Injector;

class Writer {
public:
  virtual void write(std::string s) = 0;
};

class StdoutWriter : public Writer {
public:
  // Like "StdoutWriter() = default;" but also marks this constructor as the
  // one to use for injection.
  INJECT(StdoutWriter()) = default;
  
  virtual void write(std::string s) override {
    std::cout << s;
  }
};

class Greeter {
public:
  virtual void greet() = 0;
};

class GreeterImpl : public Greeter {
private:
  Writer* writer;

public:
  // Like "GreeterImpl(Writer* writer) {...}" but also marks this constructor
  // as the one to use for injection.
  INJECT(GreeterImpl(Writer* writer))
    : writer(writer) {
  }
  
  virtual void greet() override {
    writer->write("Hello world!\n");
  }
};

Component<Greeter> getGreeterComponent() {
  return fruit::createComponent()
    .bind<Writer, StdoutWriter>()
    .bind<Greeter, GreeterImpl>();
}

int main() {

  Injector<Greeter> injector(getGreeterComponent());
  Greeter* greeter = injector.get<Greeter*>();
  
  greeter->greet();
  
  return 0;
}