///////////////////////////////////////////////////////////////////////////// // apps/examples/elf/tests/helloxx/hello++3.cxx // // Licensed to the Apache Software Foundation (ASF) under one or more // contributor license agreements. See the NOTICE file distributed with // this work for additional information regarding copyright ownership. The // ASF licenses this file to you under the Apache License, Version 2.0 (the // "License"); you may not use this file except in compliance with the // License. You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the // License for the specific language governing permissions and limitations // under the License. // ///////////////////////////////////////////////////////////////////////////// // // This is an another trivial version of "Hello, World" design. It illustrates // // - Building a C++ program to use the C library and stdio // - Basic class creation with virtual methods. // - Static constructor and destructors (in main program only) // - NO Streams // ///////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////// // Included Files ///////////////////////////////////////////////////////////////////////////// #include ///////////////////////////////////////////////////////////////////////////// // Classes ///////////////////////////////////////////////////////////////////////////// class CThingSayer { const char *szWhatToSay; public: CThingSayer(void); virtual ~CThingSayer(void); virtual void Initialize(const char *czSayThis); virtual void SayThing(void); }; // A static instance of the CThingSayer class. This instance MUST // be constructed by the system BEFORE the program is started at // main() and must be destructed by the system AFTER the main() // returns to the system static CThingSayer MyThingSayer; // These are implementations of the methods of the CThingSayer class CThingSayer::CThingSayer(void) { printf("CThingSayer::CThingSayer: I am!\n"); szWhatToSay = NULL; } CThingSayer::~CThingSayer(void) { printf("CThingSayer::~CThingSayer: I cease to be\n"); if (szWhatToSay) { printf("CThingSayer::~CThingSayer: I will never say '%s' again\n", szWhatToSay); } szWhatToSay = NULL; } void CThingSayer::Initialize(const char *czSayThis) { printf("CThingSayer::Initialize: When told, I will say '%s'\n", czSayThis); szWhatToSay = czSayThis; } void CThingSayer::SayThing(void) { printf("CThingSayer::SayThing: I am now saying '%s'\n", szWhatToSay); } ///////////////////////////////////////////////////////////////////////////// // Public Functions ///////////////////////////////////////////////////////////////////////////// int main(int argc, char **argv) { // We should see the message from constructor, CThingSayer::CThingSayer(), // BEFORE we see the following messages. That is proof that the // C++ static initializer is working printf("main: Started. MyThingSayer should already exist\n"); // Tell MyThingSayer that "Hello, World!" is the string to be said printf("main: Calling MyThingSayer.Initialize\n"); MyThingSayer.Initialize("Hello, World!"); // Tell MyThingSayer to say the thing we told it to say printf("main: Calling MyThingSayer.SayThing\n"); MyThingSayer.SayThing(); // We are finished, return. We should see the message from the // destructor, CThingSayer::~CThingSayer(), AFTER we see the following // message. That is proof that the C++ static destructor logic // is working printf("main: Returning. MyThingSayer should be destroyed\n"); return 0; }