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